A ‘potentially historic’ heat wave is intensifying along the West Coast with no relief expected for days

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

Officials from California to Oregon and Washington, to 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 up 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 that 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 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 never leave anyone in a car, and to drink plenty of water, stay in the shade and wear light, loose fitting clothes.

Saturday will likely be the hottest day in this prolonged heat wave, with high temperatures in the 110s 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.

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

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. They’ll be spending a long time outside, may have little access to shade and water and may not recognize the risk,” Multnomah County’s health officer, Dr. Richard Bruno, said in a news release.

Bruno said the area as 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 dead as 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, National Weather Service—Portland, Oregon, Meteorologist Noah Alviz told CNN. “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,” he said.

“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.”

Over a dozen high-temperature records were either broken or tied on July 4, including multiple California cities, with Palmdale hitting 110 degrees and Madera reaching 109 degrees.

The stage is set for wildfire spread

The extreme heat combining with gusty winds and low humidity mean 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 over 3,700 acres in California’s Butte County since it was reported Tuesday, forcing thousands to evacuate and drawing hundreds of firefighters to battle the flames under the extreme heat in the Oroville, California, 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.

The fire was 29% contained as of Thursday night, according to Cal Fire.

The state’s been seeing an active fire season, with 144,940 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, triggered evacuation orders Thursday night after burning burned 400 acres just northwest of the small community of Mariposa, outside Yosemite National Park, Cal Fire said in a social media post.

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

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

“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.

The-CNN-Wire

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