Oregon’s largest city broke its all-time heat record on Saturday. It could beat the new mark on Sunday.  Forecasters say many Pacific Northwest communities may sweat through the hottest days in their histories as temperatures soar during a heat wave that has sent residents scrambling for relief.

Stores sold out of portable air conditioners and fans, hospitals canceled outdoor vaccination clinics, cities opened cooling centers, baseball teams canceled or moved up weekend games, and utilities braced for possible power outages.

Portland, Oregon, reached 108 degrees Fahrenheit (42.2 degrees Celsius) Saturday afternoon, according to the National Weather Service. The previous heat record for Oregon’s largest city was 107 F (41.7 C), a mark hit in 1965 and 1981.

Seattle reached 101 F (38.3 C) Saturday, making it the hottest June day on record and only the fourth time in recorded history the usually temperate city had topped 100 degrees.

The forecast was for even hotter temperatures on Sunday and Monday. Many all-time heat records could be broken. In Seattle, the highest temperature ever measured was 103 F (39.4 C), in 2009.

Other cities and towns from eastern Washington state to Portland to southern Oregon were also expected to break records, with temperatures in many areas likely to top out 30 degrees or more above normal.

That’s dangerous for a region accustomed to mild weather, and where many don’t have air conditioning.

The extended “heat dome” over the Pacific Northwest was a taste of the future as climate change reshapes weather patterns worldwide, said Kristie Ebi, a professor at the University of Washington who studies global warming and its effects on public health.

“We know from evidence around the world that climate change is increasing the frequency, intensity and duration of heat waves. We’re going to have to get used to this going forward,” she said.

James Bryant, a Seattle resident, picked up an air conditioner in anticipation of the extreme heat.

“My house is already hot, and so with the added heat over the next few days, I’ve got kids. I got to make sure they don’t get too hot as well,” Bryant said. “It seems to be a trend … So I’m not sure what’s driving it, but it’s not fun, that’s for sure.”

Officials in Multnomah County, Oregon were asking for volunteers to help staff cooling centers as older people, homeless residents and others struggled with the heat. Cascades Street Outreach, an advocacy group for people experiencing homelessness, was going to homeless camps in the region to encourage people to use the cooling centers.

The hot weather had berry farmers scrambling to pick crops before they rot on the vine. Columbia Basin fisheries managers are worried about how the heat wave will affect endangered Snake River sockeye and other species of protected salmon.

Washington Gov. Jay Inslee lifted Covid-19 capacity restrictions on publicly owned or operated and non-profit cooling centers in light of the heat. Capacity is currently limited to 50% until the state fully reopens next Wednesday. In Oregon, Gov. Kate Brown suspended capacity limits for movie theaters and shopping malls — places with air-conditioning — as well as swimming pools ahead of a statewide reopening Wednesday.