Heat in California: A “potentially historic” heat wave is intensifying on the West Coast, with no improvement expected for several days


An extremely dangerous, unusually long heat wave is intensifying and spreading along the West Coast – and it will not improve for days.

From California to Oregon to Washington to Nevada to Arizona, authorities are preparing for possible wildfires, opening cooling centers and warning residents to stay indoors and stay hydrated as the ongoing heat wave brings sweltering temperatures well above 100 to 113 degrees Fahrenheit (38 to 45 degrees Celsius). Highs of up to 120 degrees Fahrenheit (49 degrees Celsius) are possible in the desert Southwest.

And it's getting hotter and hotter.

In Death Valley in California, temperatures could exceed 48 degrees on Sunday or Monday, setting a new daily record for these days. In Las Vegas in Nevada, the maximum temperature could also exceed 46 degrees on Sunday or Monday.

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

Extreme heat is one of the leading causes of weather-related deaths in the United States, claiming hundreds of lives each year, according to the National Weather Service.

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

On the same day in Arizona, a 10-year-old died after suffering a heat-related emergency while hiking with his family in South Mountain Park and Preserve, Phoenix police 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, drink plenty of water, stay in the shade and wear light, loose-fitting clothing.

Saturday will likely be the hottest day of this ongoing heat wave. Temperatures across California, outside of coastal areas and higher elevations, are expected to reach around 110 degrees Fahrenheit (43 degrees Celsius), the National Weather Service said.

“This heat in parts of the Mojave Desert and the Sacramento/San Joaquin Valleys of California could pose a danger to everyone if proper heat protection measures are not followed,” the weather service said.

Nationwide, heat warnings remain in effect for nearly 140 million people, primarily in western states where the heat wave is expected to last until the middle of next week.

Parts of Oregon are expected to see triple-digit temperatures on Friday, and the heat could last up to five days with little precipitation overnight, the National Weather Service Portland says.

With temperatures expected to rise, Multnomah County, Oregon's most populous county, has declared a state of emergency for this weekend.

“I am especially concerned about the thousands of people traveling to music festivals and sporting events this weekend. They will be spending a lot of time outdoors, may have little access to shade and water, and may be unaware of the danger,” Multnomah County Health Officer Dr. Richard Bruno said in a news release.

Bruno said there have been few hot days in the area so far this year and residents' bodies have not yet adjusted to the heat.

During an earlier heatwave in Oregon in 2021, dozens died when electrical systems failed in the heat, and temperatures over 100 degrees Fahrenheit caused power outages for tens of thousands.

Although this heat wave is not expected to be as intense as the scorching heat wave of 2021, meteorologists are concerned that it will last a long time, meteorologist Noah Alviz of the National Weather Service in Portland, Oregon, told CNN. “Four to five days of temperatures above 95 degrees or even 100 to 105 degrees. That's very unusual for this place,” he said.

“Triple-digit heat will extend northward into the Pacific Northwest and parts of the central Great Basin, with temperatures rising to widespread highs of 30 to 38 degrees,” the National Weather Service said. “The duration of this heat is also of concern, as above-average temperatures are expected to persist into next week.”

On July 4, over a dozen temperature records were broken or set, including in several California cities: Palmdale reached 43.3 °C and Madera reached 42.7 °C.

The extreme heat combined with gusty winds and low humidity cause forest fires to spread quickly through the already dried out vegetation.

Extreme temperature warnings are in effect across the West, including in the area of ​​the Thompson Fire, which has ravaged more than 3,700 acres in California's Butte County since it was declared on Tuesday, forcing thousands to evacuate and sending hundreds of firefighters battling flames in the Oroville, California, area in extreme heat.

According to Chris Peterson, a spokesman for the California Department of Forestry and Fire Protection (also known as Cal Fire), 11 firefighters were injured in the wildfire, including eight who suffered from heat-related illnesses.

According to Cal Fire, the fire was 29% contained as of Thursday evening.

The state is currently experiencing an active fire season; according to Cal Fire, 144,940 acres have burned so far in 2024, compared to 7,812 acres during the same period last year.

There are currently nearly two dozen active wildfires of varying sizes raging in California, and the Thompson Fire is one of the largest, according to Cal Fire.

“We're seeing fires from the coast from San Diego all the way to the foothills in Butte,” Cal Fire deputy director Nick Schuler told CNN on Wednesday. “Our firefighters are fighting fires across California and are often on the scene for more than 24 hours. They're facing difficult conditions.”

A wildfire in California's Mariposa County, known as the French Fire, triggered evacuation orders Thursday evening after burning 400 acres northwest of the small community of Mariposa outside Yosemite National Park, Cal Fire said in a social media post.

A curfew has been imposed on two hotels near Yosemite National Park because of the forest fire, the Mariposa County Sheriff's Office said Thursday evening.

California Governor Gavin Newsom declared a state of emergency for the Thompson Fire area on Wednesday, paving the way for additional resources, including the ability to mobilize the California National Guard to assist.

While the West swelters, the oppressive heat and humidity will shift eastward toward the Mid-Atlantic and Southeast toward the end of the week.

“Warm temperatures between 25 and 27 degrees Celsius overnight will provide little relief and will create a dangerous situation for those without access to adequate cooling,” the National Weather Service said.

New heat advisories have now been issued for southeast Texas, extreme southern Florida, and parts of the Southeast into the mid-Atlantic, where highs will range between 95 and 104 degrees Fahrenheit. Cities like Houston, Miami, Atlanta, Raleigh, and Washington, DC will feel the heat.

The heat index values ​​in these areas – how the air feels to the human body – are between 100 and 115 degrees.

“A cold front moving into the southern Plains is expected to bring cooler and below-average temperatures across Oklahoma, much of North/West Texas and the Mid-South through Friday,” the weather service said.