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Historic Heat Wave Scorches Western U.S., Shattering Records and Prompting Warnings
An unprecedented heat wave has gripped much of the western United States, plunging cities and their residents into summer-like conditions months ahead of schedule. Temperatures soaring 20 to 40 degrees Fahrenheit above average for this time of year have led to the shattering of more than 150 daily and 50 monthly temperature records since the start of the week.
The blistering conditions, which have persisted across California and the desert Southwest, are expected to build and spread eastward into the central U.S. in the coming days, according to the National Weather Service.
In California, Death Valley registered a scorching 105 degrees on Thursday, marking a new monthly record. Forecasts indicate highs will remain well into the triple digits there into next week.
Southern Nevada has also been grappling with the early heat. Las Vegas hit 96 degrees on Saturday, with temperatures expected to remain high through Sunday. In response, more than 40 daytime cooling stations have been opened across the city to help residents cope.
“While Southern Nevada is no stranger to extreme heat, we are facing an unprecedented heat wave months ahead of the summer season,” stated Clark County Commissioner Marilyn Kirkpatrick earlier in the week. “Our bodies are not yet acclimated to these temperatures, and that puts people at greater risk for heat-related illnesses.” The National Weather Service office in Las Vegas urged residents to take proper precautions, advising the use of sunscreen, light meals, and avoiding caffeine and alcohol when outdoors.
Further east, Colorado experienced remarkable highs. Fort Collins reached an astonishing 91 degrees on Saturday, setting a new all-time record for March since recordkeeping began in 1893.
This milestone even surpassed April’s hottest recorded temperature in Fort Collins by two degrees. Denver, too, hit a new March record on Saturday at 86 degrees.
The combination of heat, low humidity, and breezy winds across Colorado is significantly elevating the risk of wildfires.
The cause of this historic heat wave is attributed to a “heat dome,” a persistent ridge of high pressure that has effectively trapped hot air over a vast area of the western U.S. like a lid. While disentangling the exact influence of climate change on individual extreme weather events can be complex, global warming is known to contribute to heat waves becoming more frequent, more intense, and longer-lasting. A recent report from the World Weather Attribution group concluded that this March heat wave “would have been virtually impossible without human-induced climate change.”
In Phoenix, where temperatures hit 105 degrees on both Friday and Saturday – record highs for the entire month of March – several popular hiking trails have been closed during daytime hours. These closures, part of the Phoenix Trail Heat Safety Program established in 2021, have been implemented months earlier than typical annual heat protection measures.
Trails at Camelback Mountain Preserve, Phoenix Mountains Preserve, and South Mountain Park and Preserve will remain restricted from 8 a.m. to 5 p.m. local time through Sunday. The Maricopa County Department of Public Health, encompassing Phoenix, advised residents to stay indoors with air conditioning as much as possible, to drink plenty of water, limit outdoor activities during peak heat, and check on vulnerable loved ones.
The extreme heat has also forced adjustments to numerous outdoor events in the Phoenix area. At least 10 Major League Baseball spring training games, for instance, moved their start times from the afternoon to after 6 p.m. local time to avoid the triple-digit temperatures, according to the Cactus League. In Glendale, the local fire department reported transporting approximately 30 individuals to area hospitals for heat-related illnesses during the Luke Days Air Show on Saturday, with many more evaluated and treated on-site.
Looking ahead, the National Weather Service anticipates temperatures on Sunday will remain in the 90s and 100s across the Southwest, with highs in the 80s in parts of Utah, Idaho, Wyoming, Colorado, and New Mexico. Across the Great Plains, residents can expect temperatures ranging from the 70s into the 90s.