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Record-breaking extreme heat continues to bake the Southwest on Sunday
01:47 - Source: CNN
CNN  — 

Western states face another sweltering day in a record-breaking heat wave that has more than 18 million people under heat alerts.

The heat will extend over southeast Oregon, northern California, the Mojave Desert, eastern California, and parts of Nevada and Utah, according to CNN meteorologist Michael Guy.

The ridge of high pressure is expected to level out, bringing more typical temperatures back to the area, with alerts beginning to expire Monday and some lasting to Tuesday evening.

The cooling will be a welcome relief to an area that has been baking under dangerous temperatures.

Andrew Phelps, Oregon Office of Emergency Management director, said the drastic changes in weather “are things none of us have experienced and have no muscle memory to rely on.”

“We’re experiencing historic flooding in places that didn’t used to flood, fire in places that didn’t use to burn,” Phelps said.

Oregon’s medical examiner confirmed 83 heatwave deaths as of July 9 and said 32 other deaths are being investigated. The state’s hospital surveillance database showed more than 800 heat-related illness visits between June 24 and July 4.

In California, wildfires have burned more than three times as much land so far this year than in 2020, when the state went on to record its worst fire season ever. There have been 4,991 fires in California since January, mostly due to extremely hot and dry conditions, according to a tweet from the California Department of Forestry and Fire Protection (Cal Fire).

By this time last year, roughly 700 fewer fires had burned across the state.

More than 103,000 more acres have burned this year through July 11 than in 2020, according to updated data from Cal Fire on Monday.

Earlier this month, temperatures reached 15 to 30 degrees above normal, Guy said. Much of the West is expected to remain 5 to 10 degrees above average, he added. During this part of the long duration heat wave, at least seven locations broke or tied their all-time record high temperatures. Guy said.

Las Vegas hit a high temperature Saturday of 117 degrees Fahrenheit. This was the fifth time the city reached this all-time record temperature since July 24, 1942.

Another concern is the record overnight temperatures.

Overnight low temperatures in portions of the Desert Southwest have failed to fall below 90 degrees. When it doesn’t get cool enough overnight, the human body is more susceptible to the effects of heat stress, putting people at greater risk of heat stroke and death, Guy said.

People visit a thermometer Sunday in Death Valley National Park.

55 large fires burning

In California and Nevada, residents are being asked to conserve energy in response to heat and wildfires.

In a tweet posted Sunday afternoon, NV Energy said the extreme heat and out-of-state wildfires are impacting the transmission lines in the region, which is affecting the energy supply.

“Thank you for conserving energy today between 6 p.m. and 9 p.m. to help reduce the strain on the electric grid,” the tweet said.

Electrical transmission lines from southern Oregon to California are still being impacted by the Bootleg Fire, a news release from the California Independent System Operator (California ISO) said. The fast-moving fire, which started on July 6, isn’t expected to be contained until November 30.

The Bootleg fire has destroyed seven structures and threatens 1,926 more, according to Bootleg fire public information officer Brad Bramlett.