Extreme weather warnings covered about 40 million residents across the western U.S. on Sunday, as the heat dome broiling the region reached its most intense point.
Meteorologists cautioned that the unusually persistent stretch of hot weather posed serious risks, describing it in some areas as “exceptionally rare” even for the middle of July. The worst conditions from the heat dome — a weather pattern that acts like a lid, holding hot air in place over an area — were concentrated across the northern Plains, the Rockies and parts of the desert Southwest. Still, the National Weather Service said dangerous heat would periodically push farther east while persisting across the central part of the country into next weekend.
The dome of high pressure strengthened over the West after a powerful heat wave — the summer’s first to combine such broad reach with such intensity — began baking the region last week. Forecasters said communities should prepare for widespread afternoon highs from 105 to 115 degrees, temperatures capable of shattering numerous local records and worsening wildfire danger. Officials also emphasized the increased threat of heat-related illness, including potentially deadly heat stroke.
“Extremely hot daytime highs combined with potentially record-warn lows will result in increasing heat stress over the next several days due to limited relief,” the weather service said in an advisory.
In Montana, the weather service office in Billings said some locations could approach or set all-time temperature records on Sunday, with readings soaring deep into the triple digits and possibly reaching 112 degrees. Extreme heat warnings covered much of the state, where officials warned the conditions could put pressure on “health systems, industries, and infrastructure” and endanger people who lack reliable cooling or adequate hydration.
Salt Lake City was also expected to come close to its all-time temperature record Sunday, with forecasts calling for a high near 107 degrees. Nearly all of Utah was placed under an extreme heat warning, expected to remain in effect until Tuesday morning.
The heat extended into the Dakotas as well, where forecasters issued extreme heat warnings across large portions of both states. In Bismarck, North Dakota, the weather service warned of “dangerously hot,” conditions, with heat index values climbing to between 100 and 110 degrees through Monday and overnight lows in the 70s providing minimal relief.
Comparable conditions were expected across much of South Dakota, where the weather service urged residents to “stay out of the sun” and “check up on relatives and neighbors,” along with other steps aimed at lowering the risk of heat-related illness.
Andrew Kozak
contributed to this report.
