A swath of the U.S. from the Pacific Northwest to the Rocky Mountains will see extreme high temperatures this week thanks to a recently formed heat dome, forecasters say.
Both high and low temperatures in states including Oregon, Washington, Northern California , Montana and Idaho could set record highs, according to the National Weather Service. Highs are expected to be in the triple digits, and lows could say above 75 degrees Fahrenheit overnight in places. Parts of interior Oregon may set records for the hottest four-day stretch recorded.
The extreme heat and the length of the heat event could pose special risks for those who don't have sufficient air conditioning, the Weather Service warned.
Wildfire risk will also be elevated, thanks to the high temperatures, low humidity and windy conditions.
Forecasters expect the high temperatures will spread south as the week progresses, ultimately resulting in a heat index around 110 in the region when high temperatures combine with high humidity.
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The extreme heat is an increasingly familiar risk. The Centers for Disease Control and Prevention says more than 600 people die due to the effects of extreme heat annually in the U.S.
In 2021, Canada confirmed 619 heat-related deaths as a result of the heat dome in the Pacific Northwest region.
One report by CNN found extreme heat has killed at least 147 people in the U.S. so far in 2023, with the total expected to climb. The count so far came from just five counties, and Maricopa County in Arizona is already investigating another 312 deaths this year that may have been due to extreme heat.
Experts say as climate change increases average temperatures, heat waves are already becoming more common, more severe and lasting longer — a trend that is expected to continue as long as greenhouse emissions keep climbing.
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