Record breaking, long-lasting heatwave grips much of western U.S.

A long-lasting heatwave continues to bring record-breaking across much of western U.S. Thursday, June 17, 2021, exacerbating the current drought situation. The National Weather Service (NWS) announced that more than 40 million residents are under a heat advisory or excessive heat warning. 

An unusually early heatwave is spreading across much of the West, with more than 300 record-high temperatures in jeopardy this week. At least 11 states have reported temperatures above 37.7 °C (100 °F).

The sweltering blast of heat began Sunday, June 13, enhancing forest fires, degrading air quality, and worsening the drought situation in some states. 

On Tuesday, June 15, historic temperatures were observed as the mercury hit 41.7 °C (107 °F) in Salt Lake City, Utah; 41.7 °C (107 °F) in Sheridan and Laramie in Wyoming; and 42.2 °C (108 °F) in Billings in Montana.

On Wednesday, June 16, Las Vegas hit a scorching 46.6 °C (116 °F)– just 0.5 °C (1 °F) shy of its highest temperature. 

Death Valley in California– which is known for setting the hottest temperature ever recorded in the world with 56.7 °C (134 °F) in 1913– hit 51.7 °C (125 °F), the highest temperature in the U.S. this year.

Denver also hit the century mark for two consecutive days on Wednesday– the earliest in the season that it saw temperatures of around 37.8 °C (100°F) twice in a row.

"What we are seeing in the Western U.S. this week– I’d be comfortable calling it a mega-heat wave because it is breaking 100-plus-year records, and it is affecting a wide region," said climate extremes expert Mojtaba Sadegh, a professor at Boise State University.

Meteorologists fear that the heat's intensity and longevity, which is the leading cause of weather-related fatalities in the U.S., may impact people's health. 

"This magnitude and duration of heat are dangerous! Limit outdoor exposure and drink plenty of water," the NWS warned Thursday, June 17, as it put more than 40 million residents under a heat advisory or excessive heat warning.

The heat has intensified the historic drought gripping the West. According to the U.S. Drought Monitor, almost 55% of the region is under exceptional drought as soil moisture is at or nearly the lowest levels seen in over 120 years in some areas. Wildfires are also feared to worsen as forecasters predict further dry conditions in parts of the West.

"My expectation is that we are going to have a dramatic fire season this year," noted Sadegh.

On Friday, June 18, the NWS warned that dangerous and record-breaking heat will continue across a large portion of the western U.S. and the central Plains.

"Heat Advisories are also in effect for portions of the Central Plains/Middle Mississippi Valley on Friday.  Well-above normal temperatures are expected across the region, with record-breaking highs expected from Kansas to Iowa and Missouri."

Image credit: Windy.com, acquired June 18, 2021.

Featured image credit: Windy.com, acquired June 18, 2021.