A ‘potentially historic’ heat wave intensifies along the West Coast, as dangerous wildfires spread

(CNN) — An extremely dangerous, unusually long heat wave is intensifying and spreading up the West Coast – and there will be no relief for days.

California, Oregon, Washington, Nevada and Arizona are bracing for potential wildfires, opening cooling centers and warning residents to stay indoors and keep hydrated as the unrelenting heat wave delivers sweltering temperatures well into the 100s and 110s – with highs in the 120s possible in the Desert Southwest.

And it’s only getting hotter.

Death Valley, California, could top 125 degrees by Sunday or Monday, setting a new daily record for those dates. Las Vegas, Nevada, could also exceed its all-time high temperature of 117 degrees Sunday or Monday.

“Confidence is increasing that this potentially historic heatwave will last several days,” the National Weather Service in Portland warned, adding the risk of heat-related illness will increase significantly.

Extreme heat is one of the leading weather-related killers in the United States, leaving hundreds of people dead each year, according to the National Weather Service.

In San Jose, California, a homeless man died Tuesday due to the extreme heat, Mayor Matt Mahan said. The man was 69, according to the mayor’s spokesperson, Tasha Dean, citing information from the Santa Clara Medical Examiner’s Office.

The same day, a 10-year-old died in Arizona after experiencing a heat-related emergency while hiking with family in South Mountain Park and Preserve, the Phoenix Police Department said.

“This is a DANGEROUS situation, especially for sensitive populations,” the National Weather Service in Los Angeles said, reminding residents to drink plenty of water, stay in the shade, wear light, loose fitting clothes and never leave anyone in a car.

Saturday will likely be the hottest day in this prolonged heat wave. High temperatures in the 110s are becoming common across California, outside coastal areas and higher elevations, the National Weather Service said.

“This level of heat throughout parts of the Mojave Desert and Sacramento/San Joaquin valleys of California could pose a risk to anyone if proper heat safety is not followed,” the weather service said.

Nationwide, nearly 140 million people remain under heat alerts – mostly in Western states, where the heat wave is expected to last through the middle of next week. More than 70 million people will be under heat alerts in parts of 10 western states on Saturday.

Parts of Oregon will experience triple digits Friday, and the heat could last up to five days with poor overnight relief, the National Weather Service in Portland said.

A state of emergency was declared in Multnomah County, Oregon’s most populous county, for this weekend as temperatures were expected to climb.

“I’m particularly worried about the thousands of people heading to music festivals and sporting events this weekend,” Multnomah County Health Officer Dr. Richard Bruno said in a news release. “They’ll be spending a long time outside, may have little access to shade and water and may not recognize the risk.”

Bruno said the area has had few hot days so far this year, and residents’ bodies have not yet acclimated to the heat.

A previous heat wave that scorched Oregon in 2021 left dozens of people dead. Power equipment buckled in the heat, triggering rolling blackouts for tens of thousands as temperatures soared above 100 degrees Fahrenheit.

While this heat wave isn’t expected to be as intense as the 2021 scorcher, forecasters are concerned about its long duration, said Meteorologist Noah Alviz of the National Weather Service in Portland. “Getting into the upper 90s or even triple digits of 100 to 105 for four to five days – that is very unusual for this location,” Alviz told CNN.

“The triple-digit heat will expand northward into the Pacific Northwest and parts of the central Great Basin, with widespread highs rising into the 90s and low 100s,” the National Weather Service said. “The duration of this heat is also concerning as scorching above average temperatures are forecast to linger into next week.”

Intense heat is expected to persist for much of the West Coast into the weekend. Major to extreme heat risk, the highest two levels, are expected for much of California and the Southwest on Saturday and Sunday, meaning health effects of heat become more likely in anyone without adequate hydration or cooling.

Over a dozen high-temperature records were either broken or tied on Thursday, including multiple California cities. Palmdale reached 110 degrees, and Madera hit 109 degrees.

The extremely dangerous and potentially deadly heat baking parts of the US also set a few all-time record high temperatures in some locations Friday.

Palm Springs, California, reached 124 degrees Friday afternoon, exceeding the previous all-time record high for the date of 123 degrees set in 2021.

An all-time record high of 105 set in 2012 was also broken in Raleigh, North Carolina, where temperatures of 106 degrees were recorded Friday.

Additional daily record highs set on Friday included:

• 114 degrees: San Jacinto, California
• 109 degrees: Medford, Oregon
• 109 degrees: Campo, California

Dozens of additional temperature records are expected to be tied or broken each of the next few days. The dangerous heat will expand into the Intermountain West and northern High Plains by next week.

The stage is set for wildfire spread

The extreme heat – combined with gusty winds and low humidity – means any wildfires that start will spread quickly through already parched vegetation.

Red flag warnings are in effect across the West, including in the area of the Thompson Fire, which has consumed more than 3,700 acres in California’s Butte County since it was reported Tuesday. The blaze, which was 55% contained by Friday afternoon local time, has forced thousands of people to evacuate and prompted more than 2,000 firefighters to battle the flames under the extreme heat in the Oroville area.

The wildfire has injured 11 firefighters, including eight who were affected by heat-related illnesses, according to Chris Peterson, a spokesperson for the California Department of Forestry and Fire Protection – also known as Cal Fire. Twenty-six structures have been destroyed by the blaze and more than 4,000 are under threat.

The state’s been seeing an active fire season, with more than 145,000 acres burned so far in 2024 compared to 7,812 acres burned by this time last year, according to Cal Fire.

There are now nearly two dozen active wildfires of varying sizes burning across California, and the Thompson Fire is among the largest, according to Cal Fire.

“We’re seeing fires on the coast in San Diego, to the foothills in Butte,” Cal Fire Deputy Director Nick Schuler told CNN Wednesday. “Our firefighters are battling fires across California and often times on the line for more than 24 hours. It’s difficult conditions that they face.”

A wildfire in California’s Mariposa County, the French Fire, injured three firefighters and destroyed four structures, according to Cal Fire. It also triggered evacuation orders Thursday night. The fire has burned more than 900 acres just northwest of the small community of Mariposa, outside Yosemite National Park, and is 20% contained as of Friday evening. More than 800 structures are under threat.

“Firefighters continue to gain containment and cool hot spots throughout the fire,” CAL Fire said in an update on its incident page Friday. “Utility crews are working diligently to repair and replace damaged infrastructure.”

California Gov. Gavin Newsom declared a state of emergency for the area of the Thompson Fire on Wednesday. The declaration cleared the path for additional resources, including the possibility of mobilizing the California National Guard to assist.

And in central Washington state, fireworks sparked an active wildfire called the Balsam Root Fire early Friday morning, according to Wenatchee Valley Fire Department Chief Brian Brett.

The fire is burning in Wenatchee, about 150 miles east of Seattle. The fire is currently around 250 acres and is 30% contained, Brett told CNN. A Level 3 Evacuation Alert is in effect for approximately 150 homes. Residents under this advisory are being told to leave immediately.

The department had previously reminded residents “private fireworks are banned in most of Chelan and Douglas Counties.”

Fireworks started an estimated 31,302 fires in 2022, according to the National Fire Protection Association.

Southeast to see sizzling temperatures, too

As the West swelters, oppressive heat and humidity will begin to shift eastward to the mid-Atlantic and Southeast for the end of the week.

“Warm overnight conditions in the upper 70s and low 80s will offer little relief, leading to a dangerous situation for those without access to adequate cooling,” the National Weather Service said.

New heat alerts are now posted in southeast Texas, extreme southern Florida and parts of the Southeast northward to the mid-Atlantic, where high temperatures will range between 95-105 degrees. Cities including Houston, Miami, Atlanta, Raleigh and Washington, DC, will be feeling the heat.

The heat index values – how air feels to the human body – will range between 100 and 115 degrees in those areas.

“A cold front entering the southern Plains is anticipated to offer cooler and below average temperatures to Oklahoma, much of northern/western Texas, and the Mid-South by Friday,” the weather service said.

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CNN’s Raja Razek, Dave Alsup, Taylor Romine, Cindy Von Quednow, Paradise Afshar, Cheri Mossburg, Amanda Musa and Zoe Sottile contributed to this report.