Heat dome drives record highs and wildfire warnings across the Western United States

A ridge of high pressure, known as a heat dome, is trapping hot air over the western United States, pushing temperatures near record levels from Arizona to Montana, National Weather Service meteorologists said. Forecasts called for 115°F (46°C) in Las Vegas, 116°F (47°C) in Phoenix and a potential 118°F (48°C) in El Centro, California, while Great Falls, Montana, could reach a record 104°F (40°C).

Meteorologists warned that overnight lows will remain in the upper 80s to low 90s, offering little relief for the body’s heat recovery. "There's just no relief overnight," said weather service meteorologist Morgan Stessman. Officials urged residents to stay indoors and stay hydrated.

In Phoenix, the Justa Center, a senior-focused facility that serves as a public cooling center, reported about 200 daily visitors seeking water, electrolytes and a place to rest. In Montana, the east side of the state was under an extreme heat warning, though temperatures are expected to drop into the 70s by Sunday, according to meteorologist Jeff Kitsmiller.

The heat wave is also amplifying wildfire danger. Montana officials noted active fires and forecast high winds, placing most of the state under a red-flag warning. In Nevada, relative humidity fell to single-digit levels in the afternoon, further drying fuels. The U.S. Forest Service warned of an elevated wildfire risk through Sunday in much of Southern California, while Washington’s governor declared a state of emergency and imposed a ban on most outdoor burning through September.

Experts linked the intensity of the current heat dome to broader climate trends, noting that rising greenhouse-gas emissions are making heat waves longer and more severe, which in turn heightens drought and wildfire risk. The ongoing El Niño event, projected to be among the strongest on record, is also contributing to the extreme temperatures.