Wildfire burns 100 homes and buildings as California braces for the worst of Labor Day heat wave

A Northern California wildfire destroyed about 100 homes and other buildings, fire officials said Saturday, amid a heat wave that has sparked a state of emergency and fueled worries about a strained power grid.

California’s heat-related problems could grow through Labor Day weekend, with temperatures expected to hit triple digits in many areas into early next week.

The wind-driven Mill Fire, which started Friday about 250 miles north of San Francisco, destroyed homes in the small town of Weed and forced residents to flee. At least two people have been hospitalized.

Crews battling the nearly 4,000-acre blaze had it about 20% contained as of Saturday morning, according to Cal Fire. Meanwhile, another nearby fire had grown and was burning near a stretch of Interstate 5 that was busy on Labor Day weekend. 

How hot will it get Labor Day weekend?

Nearly 40 million people were under excessive heat warnings on Saturday, including most of California and southern Nevada, according to the National Weather Service. Another nearly 9 million were under heat advisories in other Western U.S. states.

Many September temperature records could be broken in inland areas of California over the weekend. In Death Valley, temperatures were forecast to reach 122 degrees on Labor Day, close to the highest temperature ever recorded on earth of 126 degrees.

Elsewhere, Sacramento was expected to reach 112 degrees Monday, according to the National Weather Service. “Hot days with limited overnight relief will result in very high risk of heat-related illnesses,” the NWS said in a tweet.

More:What is the hottest temperature ever recorded? Where on Earth was it?

Extreme heat dangers over holiday weekend

Some areas, including around Sacramento, were opening cooling centers and offering tips to avoid heat illness. 

That includes staying hydrated, limiting sun exposure and avoiding the hottest part of the day. Officials urged residents to check on neighbors, beware of leaving pets or people in hot cars and make sure animals have shade and water. 

And with California facing a drought as it enters what is traditionally the worst of the fire season, Cal Fire reminded residents to avoid any activity that could start a fire, noting that about 95% of wildfires are caused by humans.

More:West Coast heat wave: About 50 million people warned of extreme heat; wildfires prompt evacuations

Power grid update

State officials hope to avoid rolling blackouts by asking residents to voluntarily use less power, even as the heat tempts Californians to crank up their air conditioners.

The California Independent System Operator (ISO) issued another statewide Flex Alert for Saturday, calling for voluntary electricity conservation on Saturday due to increasing high heat, tightening energy supplies and more potential strain on the grid.

Gov. Gavin Newsom’s office said in a statement that power demands this weekend were expected to be at the highest since the summer of 2017.