Freddie Ramirez, left, is handed a bottle of water from Kim Burrell, in Sacramento, Calif., Tuesday, Sept. 6, 2022. Burrell and Debbie Chang, right, passed out water and snacks to those they find in need on the streets. Temperatures in the Sacramento area are forecasted to reach record highs Tuesday. Rich Pedroncelli/Associated Press

A historically severe September heat wave is baking the West, breaking hundreds of records, posing a danger to public health and pushing California’s power grid to the limit. Some records have been shattered by wide margins as the scorching air mass exacerbates the fire danger in the drought-stricken region.

California’s Independent System Operator (ISO) says the state’s electric grid is under heavy strain and warned consumers “to be prepared for possible outages” Tuesday evening.

“As the state faces the hottest day in this prolonged, record-breaking heat wave, grid conditions are expected to worsen,” the grid operator wrote in a news release. “If needed, ISO could order utilities to begin rotating power outages to maintain stability of the electric grid.”

The agency, which declared an energy emergency alert, is predicting an all-time historic high demand of 52,258 megawatts Tuesday afternoon, surpassing its previous record of 50,270 megawatts on July 24, 2004.

The ISO urged residents to “precool” their homes to 72 degrees Tuesday and Wednesday mornings, and then turn the thermostat to 78 degrees during peak demand hours between 5 and 9 p.m. It has called for such reductions on seven straight days.

The heat is historic for both its duration and intensity, evidenced by long-standing monthly and all-time records that continue to be toppled. San Jose, Calif. set an all-time high of 109 degrees Tuesday afternoon.

In Sacramento, the downtown district got to 113 degrees Monday, just a degree below an all-time record set on July 17, 1975, and four degrees hotter than the previous September record. Records there date back to 1877.

On Tuesday afternoon, Sacramento is expected to jump to 115 degrees, which would be both a monthly and all-time record as well as only the 11th time in the past 145 years that the city made it to 112 degrees or higher.

“This will be essentially the worst September heat wave on record, certainly in Northern California and arguably for the state overall,” said Daniel Swain, a climate scientist at UCLA, in a Twitter Spaces discussion Tuesday. “By some metrics, it might be one of the worst heat waves on record period in any month, given its duration and its extreme magnitude, especially in Northern California and especially in the Sacramento region.”

A whopping 42 million Americans are under excessive heat warnings, including across most of California, northeast Arizona and adjacent southern Nevada. The Great Basin, southern Idaho and western Utah are under heat advisories.

“Extreme heat will significantly increase the potential for heat related illnesses, particularly for those working or participating in outdoor activities,” wrote the National Weather Service. “[There is a] very high risk of heat stress or illness for the entire population.”

WILDFIRES ALSO A PROBLEM

The excessive heat is also fueling the risk for fast-moving fires.

Red flag warnings – connoting dangerous fire weather – encapsulate the entirety of Montana in addition to northern Idaho, much of Oregon and northern and eastern Washington.

Rick Fitzpatrick holds a dog after evacuating from the Fairview Fire Monday, Sept. 5, 2022, near Hemet, Calif. Ethan Swope/Associated Press

A number of large wildfires have erupted over the last week in California, Oregon, Idaho and Montana. The fast-moving Mill Fire, which erupted Friday in Northern California, killed two people and injured three. On Monday, two people died and another was injured by the Fairview Fire, which started near the city of Hemet, which is about 75 miles southeast of Los Angeles in Riverside County.

The National Interagency Fire Center elevated the need for national fire preparedness to level 4 out of 5 because of hot, dry and windy conditions predicted for the foreseeable future.

WHEN WILL THE HEAT EASE?

The heat will begin to gradually ease Thursday, forecasters say. Temperatures closer to average will return to much of California over the weekend, although temperatures will remain somewhat above normal over the Pacific Northwest and Northern Rockies.

Around that time, moisture from Hurricane Kay in the Pacific southwest of the Baja Peninsula could begin wafting northward, lowering temperatures and possibly bringing some beneficial rainfall to Southern California and even farther north. However, its specific effects on the region are highly uncertain and it could also increase the potential for dry lightning that could increase the fire risk.