Английская Википедия:2021 Western North America heat wave

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The 2021 Western North America heat wave was an extreme heat wave that affected much of Western North America from late June through mid-July 2021. Extreme event attribution found this was a 1000-year weather event, made 150 times more likely by climate change. A study in Nature Climate Change estimated that its occurrence, while previously thought virtually impossible, is projected to increase rapidly with further global warming, possibly becoming a 10-yearly occurrence in a climate 2°C warming than the pre-industrial period, which may be reached by 2050 if fossil fuels are not phased out and carbon-dioxide emissions eliminated. The heat wave affected Northern California, Idaho, Western Nevada, Oregon, and Washington in the United States, as well as British Columbia, and in its latter phase, Alberta, Manitoba, the Northwest Territories, Saskatchewan, and Yukon, all in Canada. It also affected inland regions of Central and Southern California, Northwestern and Southern Nevada and parts of Montana, though the temperature anomalies were not as extreme as in the regions farther north.

The heat wave appeared due to an exceptionally strong ridge centered over the area, whose strength was linked to the effects of climate change. It resulted in some of the highest temperatures ever recorded in the region, including the highest temperature ever measured in Canada at 49.6 °C (121.3 °F), as well as the highest temperatures in British Columbia, in the Northwest Territories, in the state of Washington as well as a tied record in Oregon. The record-high temperatures associated with the heat wave stretched from Oregon to northern Manitoba, and daily highs were set as far east as Labrador and as far southwest as Southern California. However, the Pacific Northwest suffered the vast majority of the disruption and damage connected with the extreme weather event.

The heat wave sparked numerous extensive wildfires, some reaching hundreds of square kilometers in area, which led to widespread disruption on the roads. One of them destroyed the village of Lytton, British Columbia, the day after it had set a record high temperature for Canada. The heat also damaged the road and rail infrastructure, forced closures of businesses, disrupted cultural events, and melted snowcaps, in some cases resulting in flooding. The heat wave also caused extensive damage to crops across the region, which was seen as likely to result in higher food prices globally, though the losses have yet to be calculated. The National Oceanic and Atmospheric Administration (NOAA) estimated that the heatwave caused at least $8.9 billion (2021 USD) in damages in the USA.

The death toll exceeded 1,400 people, with a death toll of at least 808 estimated in western Canada. The Chief Coroner of British Columbia reported that in the week between June 25 to July 1, 619 deaths were due to heat exposure. Confirmed deaths in the United States include at least 116 in Oregon (of which 72 are in Multnomah County, which includes Portland), and at least 112 in Washington and one death in Idaho; An analysis by The New York Times suggests that around 600 excess deaths occurred the week the heat wave passed through Washington and Oregon.

Meteorological history

Файл:500-mb pressure chart 2021-06-28 700EST Heat dome Pacific NW.png

Geopotential height chart at 500 millibars at 11:00 UTC on June 28, 2021. The center of the heat dome, which caused the heat wave, can be seen over the British Columbia Interior.

On June 23, the United States National Weather Service warned of an approaching heat wave in the Pacific Northwest, whose origins could be traced to torrential rains in China. There, the warm, moist air rose and was eventually entrained by the jet stream, which transported it east over cooler waters. When that air current encountered an upper-level high-pressure zone, also called a ridge, it started to significantly deform on June 25, forcing to accommodate the high-pressure area south of the jet stream's meander. At the same time, the Southwestern states were enduring an intense drought, which had earlier allowed higher-than-average temperatures over the Southwestern United States, leading to a similar hot wave earlier in June. Its remnants then moved north to the Pacific Northwest. Six days later, Environment Canada issued a heat warning for Alberta, Saskatchewan, British Columbia, Manitoba, Yukon, and Northwest Territories.

Файл:Heat Wave.jpg

Formation of a heat wave via a heat dome. In this scenario, the high-pressure area forces the air downwards, heating the air column, but even as the air becomes increasingly lighter and hotter due to the sun's energy, it cannot escape the dome because of the high pressure. This situation has been compared to pressure cooking.

These conditions made way for a massive Rex block, which is more often formed during La Niña years. In this situation, a high-pressure area stays in place for a long time and does not let cyclones pass through it, which could have cooled the region; in this particular case, the high-pressure area was sandwiched between two stationary lows, which prevented the high-pressure region from moving anywhere. As the Pacific Northwest, just as the Southwest, experienced severe drought conditions, the already warm air was heating more quickly than usual, which intensified the ridge so strongly it caused a heat dome. Indeed, on June 27, the height at which 500 hPa air pressure was sustained (geopotential height) was reported at Шаблон:Convert in Prince George, British ColumbiaШаблон:Sndthe highest ever recorded in the area; adjacent stations have similarly reported record-high values. The downslope winds from the Cascades and other mountain ranges further warmed the air in the valleys.

After the heat dome hovered over British Columbia and the Northwestern United States for a few days, it began to move eastward, breaking records east of the Rocky Mountains, particularly in the northern parts of the Prairie provinces, but bringing relief to the Pacific coast. At this stage, the heat was kept between the warm and cold fronts of the low-pressure area that formed over southern Northwest Territories and was transported eastward towards Hudson Bay. Sweltering conditions were observed as far east as Montana, Manitoba, and Northwest Ontario, Шаблон:Cnspan

By July 4–5, the remnants of the heat dome crossed Hudson Bay and, weakened somewhat by the cool waters, entered Quebec, and after that, Labrador, briefly triggering temperatures of around Шаблон:Convert. Шаблон:Cnspan

Climate change and additional factors

Climate change in Canada and in the United States are widely considered to have worsened the heat wave's unprecedented intensity and duration. According to a preliminary study, which has not yet been peer-reviewed, the heat wave would have been highly unlikely in the absence of anthropogenic climate change, the latter increasing the likelihood of such a heat wave at least 150-fold. According to this study, either the climate change made the heat wave more likely by increasing base temperatures and a combination of rare events, such as the recent drought and/or changes in the jet stream, resulted in the heat wave, or even a relatively small increase in mean global temperatures caused by climate change can pass a threshold that triggers a sharp increase in the probability of extreme heat wave phenomena.

While it is yet unknown whether the frequency of these omega blocks is due to global heating, according to the data provided by Verisk, the Pacific Northwest is among the fastest-heating regions in the continental United States and southern Canada. Moreover, the urban heat island effect could have further exacerbated the impact in cities. Based on historic data, several meteorologists noted that this phenomenon should be expected to occur only once over a thousand or several thousand years, and David Sauchyn, a scientist at the University of Regina, said that climate models had been predicting the heat wave of a similar intensity to happen in late 2020s at the earliest.

Temperature records

Much of the Pacific Northwest, normally known for its temperate weather in June, received maximum temperatures Шаблон:Convert above normal during this heat wave. In fact, the temperatures were so anomalous that nighttime lows were higher than the average high temperatures that this region would normally observe at this time of year. Ground temperatures were also reaching extremes - in Wenatchee, Washington, it reached Шаблон:Convert, while the pavement at an intersection in Portland, Oregon reached Шаблон:Convert.

This heat wave, combined with other extreme weather occurrences elsewhere, yielded the hottest June on record in North America. It also contributed to the hottest June ever for some localities such as Victoria, Abbotsford, Kamloops and Edmonton, and in Portland, Oregon, as well as one of the hottest June mean temperatures for Seattle and Spokane. On a statewide level, June 2021 was the warmest on record in California, Nevada, Arizona, Utah and Idaho, and second warmest for Washington, Oregon and Montana, at least partly attributable to this heat wave.

Canada

The highest temperatures of the heat wave were registered in British Columbia, but areas as far east as Ontario were affected by the event. Шаблон:As of 103 all-time heat records were set across Western Canada.

British Columbia

On June 28, records were set in Squamish, British Columbia at Шаблон:Convert, Abbotsford at Шаблон:Convert, Port Alberni at Шаблон:Convert and Victoria at Шаблон:Convert. Also, on the morning of June 28, a meteorological station at Simon Fraser University in Burnaby registered an overnight low of Шаблон:Convert, Шаблон:Cnspan

On June 27, local records were also set in Cultus Lake, Lillooet, Ashcroft (Шаблон:Convert) and Kamloops (Шаблон:Convert). In all, there were 59 weather stations in B.C. that set records for hottest temperatures recorded for June 27. These were largely beaten in the following days (Kamloops, for instance, registered Шаблон:Convert on June 28 and Шаблон:Convert on June 29, the peak temperature recorded in a major population center in the region).

On June 29, the temperature in Lytton, British Columbia, hit Шаблон:Convert, the highest temperature ever recorded in Canada, although a nearby more modern station reported that the extreme was 1 °C lower. The stations were temporarily isolated by the Lytton wildfire the next day. The record occurred after consecutively setting new record highs of Шаблон:Convert on June 27 and Шаблон:Convert on June 28. It is also the highest temperature ever recorded north of 45°N, the highest temperature in the U.S. or Canada recorded outside the Desert Southwest, and higher than the absolute maximum temperatures of Europe or South America.

Alberta

In Alberta, the highest heat was observed in the period from June 29 to July 1. Banff Шаблон:Convert, Beaverlodge Шаблон:Convert, Cochrane Шаблон:Convert, Fort McMurray Шаблон:Convert, Jasper Шаблон:Convert, Grande Prairie Шаблон:Convert, Hendrickson Creek Шаблон:Convert, Nordegg Шаблон:Convert, Red Earth Creek Шаблон:Convert all saw the strongest heat ever measured in these communities, most after breaking all-time records of the previous day.

Calgary noted Шаблон:Convert on June 29 and July 1, which stopped just 0.2 °C (0.4 °F) short of the highest observed temperature ever and beating the all-time records for June and July. Edmonton also saw temperatures approach the absolute maxima – the city centre registered Шаблон:Convert on June 30, while the Edmonton International Airport, near Leduc, hovered around Шаблон:Convert from June 29 to July 1. The heat wave had largely moved east by July 2, though, e.g., Fort McMurray measured its fourth daily record in a row on that date.

Territories

In the Northwest Territories, on June 28, Nahanni Butte set a regional record at Шаблон:Convert. Two days later, Fort Smith, just north of the Alberta border, reached Шаблон:Convert, which beat the previous all-time territorial record, registered in the same place in 1941. It was also the new highest reliably recorded temperature above 60 degrees latitude.

Yukon was largely bypassed by the heat wave, but on June 28, some areas in the territory went over Шаблон:Convert, including Whitehorse (Шаблон:Convert) and Teslin (Шаблон:Convert), both of which were daily records. Teslin also beat the record for June 29, at Шаблон:Convert.

Saskatchewan

Saskatchewan's heat records were mainly concentrated in the northern parts of the province. Stony Rapids saw the mercury reach Шаблон:Convert on June 30, an all-time high and record temperatures were also set at Key Lake Airport, sometimes dubbed "the cold pole of Saskatchewan", and Collins Bay Airport on July 1, both at Шаблон:Convert, as well as in Uranium City (Шаблон:Convert). July highs were also observed in these settlements on the first day of the month, when 26 daily records were set across the province, most in northern communities.

Elsewhere, the heat arrived slightly later. Saskatoon reached Шаблон:Convert on July 1 and beat the monthly record the following day, at Шаблон:Convert, a tenth of degree below the all-time record. La Ronge registered an all-time high with a reading of Шаблон:Convert. Regina, like most of the southern part of the province was spared the extremes reached in the northern parts, with a maximum of Шаблон:Convert on July 2. The heat wave over Saskatchewan largely dissipated by July 3 and moved east.

Manitoba

In a similar way to Saskatchewan, the majority of heat records (including all-time highs) were noted in the northern parts of the province. A remote community of Tadoule Lake observed Шаблон:Convert, beating the previous all-time record by Шаблон:Convert, so did Lynn Lake (Шаблон:Convert), while Churchill, on the shore of Hudson Bay, registered Шаблон:Convert, the highest temperature for July.

Other parts of the province did not see heat as extreme as elsewhere, though 25 daily records were set on July 3, including Шаблон:Convert in Winnipeg.

Ontario

Northwestern Ontario did not see all-time high records beaten, but several daily records were pushed higher: on July 3, Thunder Bay equalled Шаблон:Convert, Geraldton saw Шаблон:Convert, while the hottest temperature was in Pickle Lake, at Шаблон:Convert.

Newfoundland and Labrador

Weakened by interaction with the Hudson Bay waters, and having not set any records in Quebec, the heat wave arrived to the mainland part of Newfoundland and Labrador, but before dissipating in the Atlantic Ocean, it still managed to beat some daily records. Hopedale registered Шаблон:Convert on July 5, while Happy Valley-Goose Bay reached Шаблон:Convert the following day.

United States

The heat wave broke numerous records by large margins. Several large cities, including Portland, Seattle, and Spokane, experienced high temperatures far exceeding Шаблон:Convert and low temperatures higher than the area's normal daily high temperatures. The heat wave beat Washington's all-time heat record in Hanford (Шаблон:Convert) and tied one for Oregon (Шаблон:Convert at two places, including at Pelton Dam). The same temperature was noted in Peshastin in Chelan County, Washington, where temperatures soared to Шаблон:Convert on June 29, slightly surpassing the previous all-time high for the state.

Oregon

On June 26, Portland broke its previous all-time record high temperature of Шаблон:Convert, set in July 1965 and August 1981, with a temperature of Шаблон:Convert. It topped that record again on June 27, with a temperature of Шаблон:Convert. The following day, the temperature increased further to Шаблон:Convert. These extremes also beat the previous record June temperature, Шаблон:Convert set on June 26, 2006.

Salem, Oregon, reached Шаблон:Convert on June 26, its record high temperature for June. It then hit Шаблон:Convert degrees on June 27, breaking the record for the highest temperature ever recorded in that city, which was previously Шаблон:Convert. Salem then exceeded the previous day's record temperature on June 28, with a maximum temperature of Шаблон:Convert. However, not all the regions of the mid-Willamette Valley experienced extreme heat on June 28. Regions south of Salem, for example, did not see highs above mid-90s Fahrenheit on that day, likely due to cooler ocean air in the area.

The Willamette Valley also experienced extreme overnight temperature drops (twice the size of normal fluctuations) due to cooler air coming from the oceanШаблон:SndPortland cooled a record Шаблон:Convert during the night, while Salem almost approached its all-time largest temperature swing, from Шаблон:Convert to Шаблон:Convert.

Washington

Файл:Washington state high termperatures June 28, 2021.png

Predicted high temperatures for western Washington on June 28, 2021

Between 1894, when the records in Seattle began, and June 2021, temperatures over Шаблон:Convert were only noted three times; however, the Seattle-Tacoma International Airport recorded three consecutive days of temperatures over Шаблон:Convert. The temperature rose to Шаблон:Convert on June 27, beating the previous record of Шаблон:Convert, only for the record to be broken again the following day by a high of Шаблон:Convert. All of these values broke the previous June record (Шаблон:Convert, 2017) by a large margin. The suburbs farther from the coast were even hotterШаблон:Snda local radio station in Maple Valley reported temperatures of Шаблон:Convert.

On June 26, Port Angeles recorded an all-time record high of Шаблон:Convert. The Quillayute Airport weather station, also on the Olympic Peninsula, reported Шаблон:Convert on June 28, exceeding its prior record by Шаблон:Convert.

On Mount Rainier, normally freezing temperatures reached Шаблон:Convert degrees above Шаблон:Convert on June 27. The heat wave was blamed for greater glacier melt on Mt. Rainier than had been seen in the state in the past 100 years.

East of the Cascades, multiple locations such as Spokane measured record-breaking or -tying temperatures, beating several records over the period of a few days. On June 29, Spokane, Ephrata and Omak all reached their all-time records, at Шаблон:Convert, Шаблон:Convert and Шаблон:Convert, respectively. These are the hottest temperatures measured since records began for those areas. Extremely warm minimum temperatures were also noted: Ephrata's thermometers did not go lower than Шаблон:Convert on June 28 and Шаблон:Convert on June 29, and all-time highest low temperature records were set at Spokane International Airport on June 29 (Шаблон:Convert) and June 30 (Шаблон:Convert), during overnight hours.

It was even hotter on and near the Oregon-Washington border. In The Dalles, Oregon and Dallesport, on either side of the Columbia River, daytime high temperatures reached Шаблон:Convert, tying the then all-time record for the state of Washington and beating the June statewide record by 5 degrees Fahrenheit. The same heat was measured in Tri-Cities on June 28–29. The state's new official temperature record was set at Шаблон:Convert on June 29 in Hanford. The heat wave resulted in 128 all-time high temperature records set for individual weather stations across the state, including in Seattle.

California

Temperature records were observed in the northern part of the state. South Lake Tahoe observed Шаблон:Convert on June 28, beating the previous June record, and tied or beaten daily records for three days in a row. In Redding, the temperatures soared to Шаблон:Convert on June 27, a daily record, while in Siskiyou County, Montague tied an all-time high for the county, at Шаблон:Convert.

Southern California was also impacted. Palm Springs registered Шаблон:Convert on June 27, surpassing the previous daily record, while other communities, such as Palmdale, Campo and Idyllwild, tied with them.

Idaho

Being largely on the margin of the high pressure dome, Idaho did not see temperatures as extreme as elsewhere. In Lewiston, on the border with Washington, Шаблон:Convert was noted on June 29, beating an all-time June record and becoming the third-highest temperature in the history of recordings for the city. Other localities in the Treasure Valley to the east were expected to sustain triple-digit heat for a week (which is in and of itself unusual) and in general to tie or beat daily records. Boise, for example, tied one for June 29 (Шаблон:Convert) and for June 30 (Шаблон:Convert), and also recorded nine consecutive days of temperatures exceeding Шаблон:Convert, which tied the record for such a streak. Records were also beaten in the Idaho Panhandle, with Coeur d'Alene registering Шаблон:Convert, which surpassed the previous highest temperature for June and equaled the all-time high for the city.

Montana

Most of Montana was placed on heat advisories, but the areas that were most affected by the heat wave were on the extreme northwest and eastern parts of the state. Kalispell and Missoula registered temperatures of Шаблон:Convert on June 29, both daily records and Шаблон:Convert short of the record for June; Libby succeeded in doing so, setting the plank at Шаблон:Convert. In the eastern parts of the state, several daily records were also noted: Livingston reached Шаблон:Convert on June 30 and Miles City saw Шаблон:Convert two days later; Billings tied its Шаблон:Convert daily record on July 1 and had not fallen below Шаблон:Convert on July 3, while Glasgow bettered its July 1 record to Шаблон:Convert, tied the daily high record the next day, and set the highest minimum temperatures on these days (Шаблон:Convert on July 2).

Deaths and injuries

Canada

Файл:Heat wave deaths 2021 Jun-Jul US by county.svg

Deaths due to heat-related causes by county in the states of Idaho, Oregon and Washington in the United States, reported as of July 14, 2021 Шаблон:LegendШаблон:LegendШаблон:LegendШаблон:LegendШаблон:Legend

The heat wave was the deadliest weather event in Canadian history.

Over 1,000 deaths occurred due to the direct consequences of the heat wave (such as hyperthermia). Most of the deaths occurred in Canada – about 600 more deaths than usual were noted in British Columbia and 66 in Alberta. It still unknown whether any of the excess deaths in Alberta were related to the heat wave,Шаблон:Clarify but the Chief Coroner of British Columbia stated that 569 casualties could be attributed to heat. A later report put the heat-related death toll at 619. She also said that in the prior five years, only three heat-related casualties had been registered. Among the deaths reported to the provincial coroner, Fraser and Vancouver Coastal health authorities saw several times more deaths than usual, and the Vancouver Island and Interior Health health districts noted double the expected number of dead during the week from June 25 to July 1. Most of the deaths were registered on June 29.

An disproportionate number of heat-related deaths during the 2021 heat wave occurred in government-funded or licensed buildings such as longterm care facilities. Of the total heat-wave-related deaths, 47 people died in community living, assisted living or long-term care facilities. Further, 62 people died from heat exposure in social housing run or funded by the provincial government. Eight individuals who lived at Vancouver Mental Health and Substance use housing died. Records show indoor air temperatures in some long-term care facilities rose to over 30°C during the heat wave. Some hospitals were also unable to keep temperatures in a comfortable range for patients and staff. At least two Lower Mainland and one Northern hospital recorded indoor temperatures of over 32°C in the emergency department, while an acute care floor at Lions Gate Hospital got as hot as 38°C.

In British Columbia, E-Comm emergency dispatchers answered nearly 15,300 calls on June 26-27, which was about Шаблон:Nowrap above normal for the month, and also deployed the ambulances 1,850 times on June 27 and 1,975 the following day - the highest number ever recorded for the province. Delays for non-emergency calls reached up to 16 hours in extreme cases. In addition to that, some ambulances were left inoperable as the emergency service was understaffed. These setbacks led to hours-long delays. The handling of the crisis drew criticism from the paramedics unions, which forced Adrian Dix, the provincial healthcare minister, to change the leader of British Columbia's emergencies response management to Jim Chu, former Vancouver's police chief, and to appoint a chief ambulance officer.

United States

In the United States, the death toll was lower but still in the hundreds: at least 116 deaths with confirmed heat-related causes in Oregon (72 in Multnomah County), at least 112 in Washington and one in Idaho. The New York Times analysis suggested that almost 450 excess deaths in Washington and 160 deaths in Oregon occurred during the heat wave, though it has not been demonstrated how many were related to the heat. For comparison, however, Oregon had only 12 heat-related deaths 2017–2019. Most of the deaths occurred among the elderly.

On July 13, 2021, Multnomah County, Oregon published an analysis which found that a majority of deaths occurred in households which had no air conditioning or had only fans.

A surge in 9-1-1 calls and emergency department visits related to the heat saw 1,100 people were hospitalized in Oregon and Washington; and almost 2,800 heat-related emergency department visits were made on July 25–30. The Washington Department of Health estimated that over 2,000 such visits occurred statewide, not including visits to Veteran Administration or the military hospitals. In Portland, the number of calls and the response times doubled, setting a record for the area. On the other hand, in Oregon, while the number of heat-related visits skyrocketed, the total number of emergency visits stayed in the expected range. Non-emergency municipal services were also strained—on June 26, the non-emergency health information service (2-1-1) did not respond to 750 heat-related calls due to lack of working staff.

Some deaths also occurred among those seeking cooling in the Pacific Northwest's rivers. Two swimmers in Salem, who were trying to escape the heat, went missing in the Willamette River, another did so in Portland, while in Washington, three people drowned. With 30 deaths in King County, it was the deadliest weather event in the county. In fact, with 112 deaths, this became the deadliest weather event in Washington State history. The total damage in Washington State was between $500 million and $1 billion.

Impact

Air conditioning

The heat wave was a problem for major cities in the Northwest. Seattle and Portland had the lowest and third-lowest percentage of air-conditioned households among major metro areas in the United States, respectively. In 2015, a U.S. Census Bureau survey found that only 33% of Seattle homes have air conditioning (A/C) units, but that number increased to 44% in the 2019 survey, likely due to the warming trend in that area (Portland had 79% coverage, which was still below the national average). The rate of air-conditioned households was even lower in British Columbia despite marked increases over the years – BC Hydro estimated that only 34% of the province's residents were using these cooling appliances, while a separate analysis indicated that only 21% of Metro Vancouver's households used air conditioning in 2017 (the number was only slightly higher for Edmonton and Calgary, at 29% and 24%, respectively). Authorities therefore waived restrictions related to COVID-19 for designated cooling shelters in Oregon, Washington, and British Columbia.

Trying to stay cool, residents in the Pacific Northwest and Alberta rushed to buy A/C units, which significantly increased their prices (some double the normal), created long installation and delivery backlogs, and ultimately made them unavailable in many stores. The pent-up demand for cooling forced electricity consumption to soar to record-high summer values. BC Hydro reported a peak of 8,500 MW, AESO registered 11,721 MW (8 MW short of an all-time high), SaskPower recorded 3,547 MW, while several electricity providers in Washington also logged record values. It also prompted power utilities in Alberta, Idaho (Idaho Power) and eastern Washington (Avista) to formally ask to conserve energy. The warning had the Idaho State Capitol voluntarily turn off lights as a result, while in the Spokane area, power outages were rolled in an attempt to prevent strain on the power grid.

Some residents chose to shelter from the heat by booking rooms in hotels, which often ran out of air-conditioned accommodation. According to CoStar calculations, the search for cooled rooms made the hotel occupancy in British Columbia reach the highest levels since the beginning of the COVID-19 pandemic, while Washington County, Oregon (suburbs of Portland) hotels reported occupancy levels at or exceeding Шаблон:Fraction of total capacity on June 26–28, more than double the rate from 2020.

Infrastructure

Файл:Emergency repairs to Interstate 5 in Shoreline, WA due to heat wave.jpg

Emergency repairs to a heat-damaged section of Interstate 5 in Shoreline, Washington

The heat wave strained and damaged the region's infrastructure. It caused the sidewalks to buckle due to thermal expansion of concrete (57 sidewalks were damaged in Edmonton alone). In Washington and Oregon, damage was even more severe, leading to closures of roads and other inconveniences for drivers, including on some lanes of Interstate 5, as well as some state highways. In order to prevent thermal fatigue to Seattle's steel drawbridges, the city announced it would hose them down with cool water.

Public transportation also deteriorated during the sweltering conditions. Trains on Link light rail and Sounder commuter rail in Seattle operated at reduced speeds as a precaution against possible deformation of railroad tracks and overhead lines. In the Portland metropolitan area, TriMet suspended MAX Light Rail and WES Commuter Rail service for part of June 27 and all of June 28 because the cables from which the light rail cars drew electricity had sagged. Heat-induced rail distortion, called sun kink, slowed down the passenger service on the route of the Amtrak Cascades. Moreover, school districts in Kamloops, Sooke (BC), Ephrata and Royal City (WA) all suspended school bus services, while Grant County, Washington limited the frequency of the buses under their management as they did not offer air conditioning or the built-in version could not cope with the heat.

On June 28, 15 school districts in British Columbia's Lower Mainland, including all districts within Vancouver, closed due to the heat and their lack of sufficient cooling infrastructure; many others also changed, or shortened, Tuesday schedules to avoid daytime high temperatures. COVID-19 vaccination sites also endured disruption because of the weather conditions.

Businesses and workers

Local businesses faced a choice to continue to work under oppressive heat or make a day off. Some restaurants, food stands and cafés closed, fearing excessive heat at the workplace or spoilage of solid products. Similarly, numerous grocers were forced to shut down aisles and halt the sale of perishable goods or use plastic sheets as impromptu thermal shields, as refrigeration units failed under the load. The businesses that decided to stay open often provided de facto sheltering from heat or converted parts of buildings to cooling centers, such as Amazon.

In a few cases, workers in California and Oregon protested the lack of air conditioning and staged local walkouts, and agricultural trade unions had also noted increased calls to strike. An SMS survey among 2,176 farmworkers in Washington (mostly in the eastern part of the state) conducted by United Farm Workers, a labor union, reported that almost all farmers did not consider protections mandated by the state OSHA sufficient. Among the surveyed, about two-fifths reported not having had shade, just under a third not having received heat illness prevention training and a quarter of respondents had no access to cool water.

After Sebastian Francisco Perez, an outdoor farm worker in St. Paul, Oregon, died while at work, Oregon OSHA faced calls to enforce safety rules for dealing with the heat wave, which had been first drafted in May. In response, Oregon's governor, Kate Brown, directed the agency to enforce the safety regulations for 180 days pending permanent implementation. In Washington state, the heat wave prompted state agencies to roll out additional protections. The Washington Post reported that the federal Occupational Safety and Health Administration was also considering a set of heat-related safety rules, whose implementation was said to be a "top priority" for the Biden administration.

Culture and sports

Sports events were disrupted by the heat wave. In Eugene, where the qualifiers for the 2020 Summer Olympics were held, the heat caused evacuation of the stadium in the afternoon and postponement of some events to the evening hours, as the temperature of the stadium's track exceeded Шаблон:Convert. It also caused an athlete to withdraw from the race.

Among other disruptions, a public swimming pool in Seattle's Rainier Beach neighborhood was closed due to dangerously high deck temperatures, so was a senior's center in Rathdrum, Idaho and a golf course on Vancouver Island. Some local concerts were also moved to avoid the heat.

Agriculture

Шаблон:See also Farms have experienced serious losses, as the heat wave baked the fruits and berries or otherwise destroyed the crop and the drought conditions worsened.

10 million pounds of fruit per day were being harvested in the Pacific Northwest at the time the heat wave struck. Farmers in Eastern Washington, facing a loss of the cherry and blueberry crop, sent workers into orchards at night to avoid the heat in the day. The British Columbia provincial fruit growers association estimated that 50 to 70 percent of the cherry crop was damaged, effectively "cooked" in the orchards. Raspberry and blackberry farms in the Lower Mainland, Oregon and Washington have also endured losses. In Whatcom County, Washington, which produces four-fifths of raspberries in the United States, estimates varied from quarter to half of the harvest; elsewhere, they went as high as 80-90%. Lettuce producers in the Okanagan Valley were also reported to be struggling with spoilt crops, so were those who grew Christmas trees and apples. In contrast, grapevines in Oregon and Washington did not seem to have sustained much damage, and corn in Skagit County, Washington was growing much ahead of schedule.

Farmers in the United States have also seen reduced yields of soft wheat, which additionally saw the quality deteriorate (68% of wheat harvest in the Pacific Northwest was estimated by the USDA to be of poor or very poor condition). In the Prairie provinces, an infestation of grasshoppers is threatening cash crops and farmers were reported to be struggling with feeding cattle as hay and forage was found to be in short supply. Saskatchewan has therefore extended additional drought support for farmers. In Alberta, lack of rain and excessive heat saw some grain plants catch fire, which has put the harvest in jeopardy. Beaumont, Alberta issued a mandatory ban on non-essential water usage, citing drought conditions. Further east, St. Laurent and Armstrong, Manitoba declared a "state of agricultural disaster" as the heat wave worsened the drought in the region, whose water reserves were already depleted.

Environment

Wildfires

Файл:062821Yreka Fire CalFire -2wiki.jpg

Wildfire burning near Mount Shasta, California, on June 28, 2021

The heat event sparked significant fires across the West Coast and Western Canada. One of the first fires to have struck the region was the Lava Fire, burning west of Mount Shasta, California, caused by a lightning strike on June 25, and which eventually burned around Шаблон:Convert on the west slope of one of the highest peaks in the state. Some of the largest fires, such as the Beckwourth Complex Fire, grew over Шаблон:Convert. Strong winds, which were causing fire tornadoes in some places, and dry vegetation hampered efforts to contain the fires. This led to road closures, such as the U.S. Route 97 and the North Cascades Highway, suspension of airport operations in Redmond, Oregon, and evacuation of settlements adjacent to the fires. The winds were so strong that residents of Medford, Oregon, Шаблон:Abbr Шаблон:Convert north of the fires, reported having seen ash falling from the sky.

Among the most known fires was the one that burst in the evening of June 30 in British Columbia. Then, Lytton, the settlement that had been beating national heat records in the previous days, along with several First Nations reserves, were ordered to be evacuated as a likely human-caused fire was approaching to the village, where it later did widespread destruction to the buildings. A local MP, Brad Vis, estimated damage to the settlement at 90%, while a local resident said that only "four or five houses, the post office and the church were still standing". The fire damaged roads, telecommunication and power facilities as well as the railway that comes through the settlement; two people died while hiding from the flames. The fire in the settlement forced the closure of a section of British Columbia Highway 1, part of Trans-Canada Highway, as well as Highway 12, which ends in Lytton. In total, 300 fires were ravaging the province as of July 13, and the wildfire season destroyed around Шаблон:Convert of forests by July 15. Pyrocumulonimbus clouds formed due to such extensive burning, producing several hundred thousand lightning strikes in one day and further complicating efforts to contain fires.

Despite deployment of more than 9,000 firefighters in the United States to extinguish them by July 1 and more than 17,000 by mid-July, the size and number of the fires grew. Almost Шаблон:Convert of forest were consumed by large wildfires, and more than Шаблон:Convert were burnt in the United States as of July 15. The intensity of the fires moved the US fire preparedness alert level to 5 (highest) by July 14, which was an early start of the wildfire season. In addition to that, Governors Kate Brown of Oregon, Jay Inslee of Washington and Brad Little of Idaho declared states of emergency due to the extreme risk of wildfires. The Canadian army officials set up a coordination center in Edmonton in order to assist wildfire actions in British Columbia, which would be directed until July 19. Higher-than-average burning also appeared in Albertan, Saskatchewan and Manitoba forests.

As the extreme heat and dry conditions persisted, scientists, firefighters and various politicians urged residents not to use fireworks during Independence Day celebrations in the Western United States and on Canada Day in Alberta. In addition to that, Washington and British Columbia enacted state-/provincewide bans on most open fires, and Washington authorities also issuing a total fire ban in state parks. Idaho and Manitoba were using more regionalized approaches, though the latter suspended all burning permits provincewide.

As of September 14, 2021, the National Interagency Fire Center (NIFC) reported that 44,647 wildfires in the United States had burned 5.6 million acres of land. Similarly, the Canadian Interagency Forest Fire Centre (CIFFC) announced that 6,317 wildfires burned 10.34 million acres. Initially, the NIFC declared that the United States and Canada had a preparedness level of 5, meaning it had the potential to exhaust national firefighting resources. Due to the earliness and severity of the wildfire season, the United States and Canada were unable to provide each other with aid as in previous years. However, by September 20, 2021, the national preparedness level was reduced to 4 and 1 for the United States and Canada, respectively.

In April 2021, the North American wildfire season was predicted to be severe due to record drought conditions and high spring temperatures in the West. In May, more than 75% of the western United States experienced drought conditions, with 21% of these conditions being deemed as "exceptional drought", which is the most extreme level of drought. These extreme conditions result in a lack of moisture on the ground that is imperative for combating wildfires. In Arizona, there were 311 early wildfires in the first four months of the year, compared to 127 in the same period in 2020.

In July 2021, haze from West Coast fires was affecting East Coast cities, and particulate pollution caused unhealthy air quality in New Hampshire.

In Montana, evacuation orders had displaced around 600 people by early August.

On October 21, the national preparedness level was lowered to 1 (indicating minimal fire activity). By November 5, a total of 48,725 wildfires had burned more than 6.5 million acres across the United States, according to the National Interagency Fire Center (NIFC).

Glacier melt

Extreme temperatures were also noted for mountain regions, which accelerated the melting of glaciers. Extensive melting occurred in the snowcaps of Banff National Park, which a glaciologist estimated that the Albertan snow from the mountains melted three times faster than usual. On Mount Rainier, the heat wave caused the mass of the snow cap to shrink by 30%, and Washington's glaciers in general have come through what glaciologists say to be the strongest melting episode in 100 years. Additionally, the increased melting of glaciers caused high amounts of runoff to be present within some rivers. The unexpected snowmelt blocked some high mountain roads in Whatcom County, Washington and rendered three hiking trails in British Columbia impassable. More importantly, it caused flash flooding down the creeks and rivers, which the glaciers feed. This triggered i.a. a week-long evacuation order in the Pemberton Valley extreme water rises were also noted in Squamish, and flood alerts were issued for other parts of British Columbia. Soot from wildfires (→ 2021 British Columbia wildfires) is further expected to diminish the mass of ice.

Wildlife and fisheries

As the surrounding air was extremely hot, water temperatures rose, which proved to be a hazard for aquatic wildlife. On the Pacific shore, temperatures in the intertidal zone reached up to Шаблон:Convert and more than a billion seashore animals, like clams, barnacles and oysters, died as a result of heat wave, impacting water quality. The deaths also impacted seafood producers, who faced losses of produce as it baked in the heatwave and started rotting. Inland, the population of sockeye salmon in Idaho rivers was preventatively caught out of water as increasing temperatures made it prone to disease; some salmon was also transported to cooler waters in the Columbia River. Fish kill, however, was not prevented in Albertan aquifers and appeared earlier than expected.

The heat wave caused an increase in vibrio bacteria levels in oysters in the Pacific Northwest, causing a record number of people to be sickened from vibriosis, an intestinal disease caused by the bacteria. The Washington State Department of Health urged people not to eat raw oysters and other shellfish from the region due to the risk of bacterial contamination.

On the land, trees in Metro Vancouver dried up and started shedding leaves; the same happened to the fir canopy in Oregon on the side where the trees faced the sun, and reportedly also in Lytton just before the wildfire swept through the community. Birds have also come through distress - in Seattle, nearly a hundred juvenile terns, whose nests were on top of an industrial building, died when they plunged to the pavement below, presumably trying to escape the heat - those that survived were treated for burns. Scores of British Columbian raptors, apart from heat exhaustion, were suffering from dehydration and starvation.

See also

• 2020–22 North American drought
• 2021 Kazakhstan heatwave
• 2021 Russia heatwave
• 2021 wildfire season
• February 2021 North American cold wave
• 2023 Western North America heat wave

Further reading

• Шаблон:Cite news
• Шаблон:Cite news
• Шаблон:Cite news
• Шаблон:Cite news

External links

• Шаблон:Commons category-inline
• www.worldweatherattribution.org:
  • Western North American extreme heat virtually impossible without human-caused climate change (7. Juli 2021)
  • Rapid attribution analysis of the extraordinary heatwave on the Pacific Coast of the US and Canada June 2021 pdf (8,6 MB)