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Scorching heat and fire danger will quickly intensify in California and the West this week as a summer-like heat dome parks itself in the region. Thermometers will exceed triple digits for the first time this year in some regions, as the early season heat wave sends daily records tumbling.
The official start of summer is just a few weeks away, but in much of the West it will feel like July as temperatures climb 20 degrees or more above the average, the highest temperatures of the year so far for many locations.
Excessive heat warnings are in effect this week for more than 10 million people in California, Nevada and Arizona. These warnings are the most extreme form of heat alert issued by the National Weather Service and are used when widespread and dangerous heat is expected.
Rising temperatures are caused by a heat dome, a large area of high pressure that parks over an area, traps air and warms it with abundant sunlight for days or weeks. The resulting heat becomes more intense the longer the heating dome lasts.
Dangerous heat will begin Tuesday in parts of California and extend its reach to more of the Southwest by Wednesday and as a heat dome parks over the West. It will then reach the Pacific Northwest at the end of the week. The most extreme heat will avoid major population centers along the coast, but Los Angeles will still be 5 to 10 degrees warmer than normal this week.
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Temperatures will rise into the 90s and low 100s Tuesday across California’s Central Valley, including where the Corral Fire is burning near Tracy.
Sacramento is expected to reach triple digits on Tuesday for the first time this year. The California capital usually hits this threshold in early June, but last year it didn’t happen until the end of the month.
Triple-digit temperatures will become widespread across the Central Valley on Wednesday and persist through the weekend. Conditions will also be very hot in the desert regions of Southern California.
Death Valley, the hottest place on earth, is expected to reach a high temperature of at least 120 degrees by Thursday. Even the brutal desert landscape doesn’t usually get this hot until mid-June.
The Southwest will begin to heat up by Wednesday as temperatures in parts of southern Arizona and far southern Nevada approach 110 degrees.
Phoenix will likely have reached 110 degrees for the first time this year by Thursday, although the city typically doesn’t experience those temperatures until mid-June. High temperatures are expected to reach 110 degrees in Las Vegas, more than three weeks before the city typically exceeds that threshold.
Early summer heat will threaten daily high temperature records across a significant portion of the West this week.
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Phoenix; Las Vegas; Flagstaff, Ariz.; Reno, Nevada; and Fresno, California, are just a few of the cities where the day’s temperature record could fall.
By Friday, records could be broken in parts of Oregon, Washington, Idaho and Colorado as heat spreads north and east.
The risk of fire will also increase when the heat is at its highest.
Sizzling temperatures and low humidity levels dry out short-fuse fuels such as grasses and brush, making them more likely to burn. Breezy winds will develop at times, especially in California midweek. The combination of these factors will make it easier for fires to start and spread.
The Corral Fire has consumed more than 14,000 acres of land in California’s San Joaquin County since it broke out south of Tracy on Saturday afternoon.
Residents were ordered to evacuate over the weekend as the fire – initially fueled by gusty winds and dry, hot conditions – threatened communities.
Firefighters gained the upper hand as winds eased Sunday and the fire was 75% contained as of Monday morning, according to the California Department of Forestry and Fire Protection.
Evacuation orders came down to warnings Sunday evening as the lockdown intensified. Authorities urged residents to remain vigilant and be ready to evacuate at a moment’s notice, according to the San Joaquin County Office of Emergency Services.
Kent PorterKent Porter/The Democratic Press/AP
A structure and vehicles burn during the Corral Fire, west of Tracy, California, on Saturday, June 1.
Two Alameda County firefighters were injured while responding to the blaze, Cal Fire Battalion Chief Josh Silveira told CNN early Sunday morning. They suffered minor to moderate injuries and were transported to a local hospital for evaluation and treatment, Silveira said.
A section of I-580 was closed in both directions this weekend as thick smoke from the fire enveloped the roadway. All lanes were reopened Sunday evening, according to the California Department of Transportation.
The cause of the fire remains under investigation, according to CAL Fire.
Wind gusts of up to 30 mph are possible through Tuesday, which could complicate ongoing containment efforts. Temperatures will also rise into the 90s Tuesday through the weekend. An excessive heat warning is in effect for the region Tuesday through Thursday.
Note: CNN original series »Violent Earth with Liev Schreiber” explores heartbreaking weather events such as wildfires, which are increasingly common in our changing climate. It airs Sundays at 9 p.m. ET/PT.
CNN’s Jillian Sykes and Dalia Faheid contributed to this report.