A "dangerous" and long-duration heat wave will build across the West this weekend through much of next week, the National Weather Service said.
Temperatures could soar to as much as 30 degrees above average, AccuWeather said.
In California, the heat will lead to increased wildfire danger and a higher threat of the spreading of the coronavirus as people flock to beaches and recreation areas.
“Dangerously hot conditions will occur during the afternoon and early evening hours each day,” a Weather Service warning said.
High pressure could push temperatures into triple digits in many places through the weekend and sweltering weather could continue into next week in the Central Valley, Sierra Nevada foothills, deserts and parts of the San Francisco Bay Area.
Palm Springs and other desert regions could approach 120 degrees and even cooler areas, such as coastal regions and portions of San Francisco, could reach 80 degrees, the Weather Service predicted.
Infamous hot spot Death Valley could soar to 127 degrees by Sunday.
Late Friday, the Golden State ordered rolling power outages for the first time since 2011 as a statewide heat wave strained its electrical system.
The California Independent System Operator (California ISO), which manages the power grid, declared an emergency shortly after 6:30 p.m. and directed utilities around the state to shed their power loads.
Pacific Gas & Electric, the state’s largest utility, tweeted that it would turn off power to about 200,000 to 250,000 customers in rotating outages for about an hour at a time. Other utilities were told to do the same.
The emergency declaration ended just before 10 p.m. and California ISO said power had been restored statewide.
“Extreme heat is really the driver behind this,” said Anne Gonzales, spokeswoman for the power grid operator.
This weekend could also feature the hottest weather in three years for several cities, AccuWeather predicted. Sacramento may reach 107 degrees for the first time since Sept. 2, 2017, and Fresno is forecast to hit the 110-degree mark for the first time since June 20, 2017.
Cooling centers have been opened in Sacramento to help residents stay cool amid the record heat.
The scorching temperatures are a concern for firefighters battling blazes that have destroyed several homes and have erupted near both rural and urban foothill neighborhoods, driving through tinder-dry brush.
In addition to the possibility of heat stroke and other hot-weather illnesses, health officers were concerned that people will pack beaches, lakes and other recreation areas without following mask and social distancing orders – a major concern in a state that has seen more than 590,000 coronavirus cases and nearly 11,000 deaths.
Excessive heat warnings and watches and heat advisories are in effect for the West Coast, Intermountain West, and the southern Plains, where record high minimum and maximum temperatures will be widespread, the Weather Service said.
In the Southwest, this summer has already gone down as the hottest on record in Phoenix with the city setting a new record for the most days with a temperature at or above 110 degrees, AccuWeather reported. The city will see highs above 110 degrees for at least the next week, the Weather Service said.
Even the normally mild Northwest will see extreme heat, as Seattle could approach a daily record of 98 degrees on Sunday, according to AccuWeather.
“Avoid strenuous activities, wear light clothing, drink plenty of fluids [and] never leave people or pets in a closed car,” the Weather Service office in Pendleton, Oregon, warned residents.
Dangerous heat is also persisting across the southern Plains, primarily across Texas and Oklahoma.
Contributing: The Associated Press
This article originally appeared on USA TODAY: Western U.S. faces high heat, rolling blackouts and wildfire worries