Heat warnings affecting more than 35 million people have appeared on the weather charts, and extreme heat watches have been issued for inland Southern California, southwestern Arizona and southern Nevada, where temperatures could exceed 115 degrees.
Warnings have also been issued for the inland deserts of Oregon and Washington, where highs could reach 100 to 110 degrees Fahrenheit. Parts of northern and western Idaho, including the Columbia River Basin, a popular summer hiking destination, could also see triple-digit temperatures. Heat warnings have also been issued for small parts of northwestern Montana.
“Heat increases the risk of heatstroke, especially without effective cooling and adequate hydration,” the National Weather Service wrote.
Dry, hot weather affects anyone outdoors, putting them at risk for rapid dehydration, which in turn strips vegetation of moisture, creating more fuel for wildfires.
High temperatures and a lack of moisture could help the ongoing fires grow, and several dry thunderstorms (which bring lightning but the rain evaporates before it hits the ground) are also expected to spark new fires, especially in southern Idaho and northern Nebraska.
The heatwaves are caused by a heat dome, or expanding ridge of high pressure that brings hot, downdrafts of air. This latest heatwave follows a two-week stretch in early July that set hundreds of records from Washington to Arizona. Las Vegas, Redding, California, and Palm Springs recorded record high temperatures of nearly 120 degrees Fahrenheit.
How hot will it get?
Heat will increase on Saturday, with temperatures reaching triple digits across much of the West, then peak on Monday and Tuesday before easing off, likely leading to many calendar records being set or broken.
- In Needles, California, on the Arizona border, temperatures are expected to reach 119 degrees, tying last year’s record, which dates back to 1888.
- Las Vegas is expected to tie the all-time record of 113 degrees, set in 1937.
- Mount Shasta in Northern California is expected to reach 101 degrees, beating the previous record of 99 degrees recorded in 2013. The previous record dates back to 1948.
- Temperatures in Las Vegas are expected to reach 114 degrees, beating last year’s record.
- In Boise, Idaho, temperatures are expected to reach 106 degrees, just shy of the previous record of 107 degrees set in 2005. Records go back to 1875.
- In Yakima, Washington, the weather service is predicting a high of 107 degrees, far surpassing the previous record of 102 degrees recorded in 2020. Records go back to 1946.
- In Omak, a small town in the northernmost part of Washington state, temperatures are expected to approach 110 degrees. The previous record was 105 degrees, set in 1938. Data goes back to 1909.
- Spokane, Washington is expected to hit 107 degrees. The previous record of 103 degrees was set in 1905. The previous record dates back to 1881.
- In Palmdale, north of Los Angeles, temperatures are expected to reach 110 degrees, beating the 109 degrees recorded last year, which dates back to 1931.
- Temperatures in California’s Mount Shasta are on track to reach 97 degrees, tying the record set in 2003.
- Boise will likely fall just short of last year’s record of 108.
- Yakima is expected to reach 102 degrees, just shy of the record of 103 degrees.
- Spokane will attempt to break the record at 103.
Temperatures will remain high through the middle of the week but won’t reach records.
Wildfire risk
Fire season has begun in the West amid relentless heat, straining firefighting resources.
There are 59 major wildfires burning across the West, including 14 in Oregon, 11 in California, eight in Montana, seven in New Mexico, and five each in Utah, Arizona and Washington.
On Thursday, the National Joint Fire Centre raised the nation’s disaster preparedness level to five out of five, signalling severe cuts to firefighters and equipment.
“Severe wildfires are currently burning in most areas, and more severe wildfires are likely to occur in the future,” the center said in its update on Thursday.
Records going back to 1990 show that only four years have seen a team reach Level 5 readiness this early in the season: 2002, 2007, 2008 and 2021.
Excessive dry lightning last week exacerbated fire conditions across the West, coming on the heels of a historic heatwave that parched the land.
Oregon has seen a series of wildfires in recent days as several large fires burn across the state, including the Falls Fire, which has burned more than 110,000 acres.
More than 9,000 lightning strikes sparked 51 fires in California between Sunday and Tuesday, some of which have already spread, including the raging Trout Fire in Sequoia National Forest in the southern Sierra.
“Lightning can spread over a wide area in a very short period of time, turning an average or busy season into a very busy season,” said Stanton Florea, a spokesman for the National Joint Fire Center.
More dry thunderstorms are expected to continue in the coming days across the Pacific Northwest and California, with several states facing above-average fire risks into the fall.
“We know this isn’t going to end anytime soon, and we could see eight to 10 weeks or more of high fire activity across the U.S.,” Florea said.
The heat has been especially tough on firefighters, who face long, tough hours working outdoors.
