Brutal Pacific Northwest heat wave suspected in seven deaths

An unrelenting heat wave that may have led to at least seven deaths weighed down on the Pacific Northwest on Sunday as temperatures were expected to soar again into the triple digits.

The National Weather Service issued an excessive heat warning for more than 10 million people across Washington, Oregon, Idaho and Northern California on Sunday. Temperatures were forecast to reach as high as 103 degrees and surpass more than a dozen daily heat records in the region.

Why is the heat significant? Saturday tied a record with six consecutive days of temperatures over 95 degrees for the Portland region, weather service meteorologist Shawn Weagle said. Temperatures ranged from 15 to 22 degrees above normal, according to the weather service.

Deadly heat waves become more frequent. In 2021, a deadly heat wave led to about 800 deaths in Oregon, Washington and British Columbia during late June and early July because of a heat dome weather phenomenon that prompted record temperatures.

When will the heat subside? Forecasters expect the heat to wane for the Pacific Northwest on Monday as a storm brings cooler air, returning the area to more normal temperatures by Tuesday or Wednesday.

More coverage of the heat wave:

• 'I'm doing the classic popsicle diet': Pacific Northwest faces unusually long heat wave

• High temperatures turn deadly: Extended triple-digit heat in Oregon investigated as cause of 4 deaths

• Beating the heat on the field: How NFL teams adjust to widespread heat wave at training camps

Deadly, record-breaking heat across Washington, Oregon, Idaho

Dozens of cities and towns from Washington to Oregon to Montana broke or far exceeded daily heat records over the weekend.

On Friday, Missoula reached 102 degrees, breaking its daily heat record for July 29. Redding, California, hit a daily record high of 114 degrees, and Medford, Oregon, hit 114, shattering its 2009 daily record of 109 and falling 1 degree short of tying an all-time high for the city.

Multiple consecutive days of triple-digit heat is atypical for a region used to moderate summer temperatures, according to Bryan Jackson, a meteorologist with the National Weather Service's Weather Prediction Center.

"Getting 20-something degrees above normal, it's definitely anomalous," Jackson said. "Getting up over 100 this number of days is rare."

The heat has been particularly dangerous because of high daily lows across the region as well, according to the weather service. Temperatures have remained abnormally high at night, making finding relief after the sunsets more challenging for residents – many of whom don't have air conditioning in their homes.

When will this heat wave end?

The Pacific Northwest is expected to see a slow cooling trend beginning Monday, according to Jackson.

"Significant relief comes Monday into Tuesday, depending on your exact location," he said. "Low pressure is expected to move into the Northwest coast, or at least a trough of low pressure through the early parts of this week."

Though the cooling trend will bring heat relief, the sustained high temperatures have led to concerns about dryness in the area, which could lead to drought conditions and wildfire risk. Parts of Montana and southern Oregon were under fire weather warnings and watches throughout the weekend.

"Dry/hot conditions make fuels very receptive to ignition," National Weather Service Seattle tweeted Sunday. "Please be careful with any and all sources of sparks."

Tips to stay cool and safe during a heat wave

Hyperthermia – an abnormally high body temperature – is suspected in the deaths of at least seven people in the Pacific Northwest since the beginning of the heat wave last week.

An elderly man in Oregon died in his home without a working air conditioner, according to Portland television station KOIN-TV. The other six possible hyperthermia deaths occurred earlier in the week in Multnomah, Umatilla and Marion counties of the state.

Jackson suggests residents wear light-colored clothing, seek out cooling centers and check in on neighbors, especially those who live alone or without air conditioning. Many of those who died in the heat wave in 2021 were older and lived alone.

Contributing: The Associated Press

This article originally appeared on USA TODAY: Pacific Northwest heat wave suspected in seven deaths