Western US Heat Wave Fuels Record Temperatures, Escalates Wildfire Threat

WASHINGTON- A powerful heat wave gripped much of the western United States on Saturday, driving temperatures toward record highs, increasing wildfire danger and prompting authorities to urge residents to limit outdoor activity and take precautions against heat-related illnesses.

The National Weather Service said a high-pressure system, commonly known as a heat dome, was trapping hot air across a broad region stretching from Arizona to Montana. Meteorologists said the episode was expected to be relatively brief but warned that dangerous conditions would persist through the weekend.

Several cities approached or exceeded historic temperatures. Las Vegas reached 115 degrees Fahrenheit (46 degrees Celsius), its highest temperature of the year and just one degree below the daily record. Phoenix was forecast to reach 116F (47C), while El Centro, California, was expected to hit a record 118F (48C). Great Falls, Montana, was forecast to reach a record 104F (40C).

National Weather Service meteorologist Morgan Stessman said temperatures in Las Vegas remained about 10 degrees above seasonal averages, with dangerous heat expected to continue into Sunday. Overnight temperatures in the upper 80s and low 90s were expected to provide little relief, increasing health risks by limiting the body’s ability to recover from daytime heat.

Authorities urged residents to stay indoors where possible, remain hydrated and seek air-conditioned spaces. Cooling centers across the region reported increased demand as vulnerable populations sought relief.

At the Justa Center in Phoenix, which serves older residents and operates as a public cooling center, operations director Rudy Soliz said the facility had been receiving about 200 visitors each day. He said the center was providing water, electrolyte drinks, meals and a safe place for people to escape the extreme temperatures.

In Montana, the eastern half of the state remained under an extreme heat warning. National Weather Service meteorologist Jeff Kitsmiller said Great Falls was expected to surpass its previous temperature record, while Helena could equal or exceed its all-time high for the date. He noted that although conditions were severe, they were less extreme than the record-breaking heat experienced in mid-July.

The Montana Rescue Mission in Billings opened its shelter earlier than usual to provide refuge from temperatures forecast to reach 106F (41C), while public swimming pools and splash parks in Great Falls experienced heavy attendance as residents sought relief from the heat.

Forecasters warned that the combination of prolonged heat, dry vegetation and gusty winds was significantly increasing wildfire risks across the western United States.

Kitsmiller said much of Montana remained under red flag warnings as existing wildfires continued to burn and forecast winds threatened to accelerate fire growth.

In Nevada, Stessman said falling humidity levels associated with the heat dome had further dried vegetation, creating conditions favorable for rapid fire spread.

The U.S. Forest Service warned of enhanced wildfire risk across most of Southern California through Sunday, excluding coastal areas.

Washington Governor Bob Ferguson declared a state of emergency on Saturday as extreme heat and strong winds intensified multiple large wildfires. He also prohibited most outdoor and agricultural burning through the end of September.

The National Weather Service issued a rare “particularly dangerous situation” red flag warning for eastern Washington, describing the fire weather threat as extreme. State officials said more than 312 square miles were burning across 12 major wildfires.

Similar warnings were in place in eastern Oregon, where firefighters continued battling several large blazes, including the Rowe Creek Complex fire, which had expanded to 490 square miles and was 57% contained.

Scientists say climate change driven by greenhouse gas emissions has increased the frequency, duration and intensity of heat waves while contributing to prolonged droughts and more destructive wildfire seasons. Experts also said this year’s weather patterns are being amplified by a strong El Niño event, which the United Nations has warned could become one of the most intense recorded since observations began in 1950.