12 Million People Are Under a Heat Advisory in the Pacific Northwest

More than 12 million people are under a heat advisory in the Pacific Northwest as temperatures through the weekend are expected to climb nearly 20 degrees higher than normal, with the extreme weather extending into Canada as the country contends with dozens of wildfires.

National Weather Service forecasters said an abnormal area of high pressure will build a “heat dome” over the western United States and Canada, acting like a lid over the atmosphere, bringing clear skies and allowing temperatures to rise.

“Temperatures in the Pacific Northwest will experience highs in the 80s and 90s, which will represent 20-30+ degree anomalies,” forecasters with the Weather Prediction Center said on Saturday. “Many parts of the coastal Pacific Northwest will tie or break temperature records this weekend.”

The Seattle region is forecast to reach a high of 87 degrees on Saturday and Sunday. If the temperature reaches 90 degrees, it will break a May 17, 2008, record for the earliest 90-degree day of the year.

Temperatures in the region are expected to be in the low to mid-80s throughout next week, forecasters said.

Several cooling centers opened throughout the Seattle area this weekend in preparation for the heat wave, according to the King County Regional Homelessness Authority.

While Portland, Oregon, has yet to open official cooling centers, local officials urged people to seek respite from the heat in local libraries, community pools or fountains. More than 43,000 bottles of water and 4,400 packets of sunscreen were also distributed to people without shelter over the past week, Portland officials said.

The hot weather will also stretch into Canada, where Alberta is fighting around 75 wildfires, 23 of which are labeled out of control, said Copernicus, an earth observation component of the European Union’s space program, on Twitter on Thursday.

Alberta has declared a provincial state of emergency and has asked more than 29,000 people to evacuate their homes.

The Copernicus Atmosphere Monitoring Service said in a news release this week that temperatures last month in Northern Canada were higher than average.

Days of abnormally high temperatures have contributed to the intensity of fires by drying out vegetation, making it more likely to ignite. Analyses have shown that climate change has increased the likelihood of such extreme heat waves.

Smoke from the wildfires has blanketed parts of the United States, causing several states along the East Coast and in the Midwest, including Virginia, Maryland and Ohio, to have moderate air quality levels instead of good, according to AirNow, which tracks air quality throughout the country.

While tying a single heat wave to climate change requires analysis, scientists have no doubt that heat waves around the world are becoming hotter, longer and more frequent.

The 2018 National Climate Assessment, a major scientific report by 13 federal agencies, noted that the number of hot days was increasing, and the frequency of heat waves in the United States jumped from an average of two per year in the 1960s to six per year by the 2010s.

Also, the season for heat waves has stretched to be 45 days longer than it was in the 1960s, according to the report.

A 2021 heat wave in the Pacific Northwest and Western Canada was exceptional, breaking previous temperature records by large margins. Worldwide since 1960, only five other heat waves have been that extreme.

Judson Jones contributed reporting.