You know it's hot when Death Valley, California, breaks high temperature records.
A long-duration, dangerous heat event is setting up for parts of the West that will begin Friday and last into next week.
More than 34 million people are under excessive heat watches and warnings across California and the Southwest. Most of the heat alerts go into effect on Friday and will stay in effect through early next week. During this time, dozens of record highs could be set in the coming days for cities like Las Vegas, Phoenix, Tucson and Salt Lake City.
This heat event will be especially dangerous due to higher than normal humidity due to tropical moisture streaming into the region from what was Hurricane Elida, which has since dissipated.
"Usually, California heat waves mean a dry heat, which is a saving grace. But what's unusual here are the remnants of Hurricane Elida, which are adding significantly more moisture into the atmosphere and will make California much muggier," said Daniel Swain, a climate scientist at the University of California, Los Angeles.
"The extra humidity makes a big difference in a bad way, from a public health perspective," Swain added.
Los Angeles will bake under temperatures in the mid-to-upper 90s through the weekend.
“If you have to do your workout outside, do it early in the day,” NBC Los Angeles meteorologist Belen De Leon said Thursday.
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Las Vegas could see temperatures soar to 113 by Sunday.
Phoenix has already had a record-setting summer, setting a new mark for most days 110 degrees or higher in a single year with 36, a number that's expected to climb over the next 7 days as temperatures soar to 115 degrees.
And Death Valley, considered the hottest place on Earth, is forecast to reach 126 degrees on Sunday and 127 degrees on Monday. If this happens, that will be the hottest temperature recorded so late in the year.
Noah Diffenbaugh, a professor of earth system science at Stanford University, said the impact of severe heat tends to fall disproportionately on marginalized groups, including people experiencing homelessness and families struggling with poverty.
People who do not have access to quality housing and air conditioning tend to be more vulnerable to heat, he said, and families with limited economic resources generally do not get as much urgent attention from emergency response systems.
"The social groups who are prioritized in emergency response to severe heat tend to be wealthier, and there's also a racial divide," Diffenbaugh said.
This intense heat coincides with fires that have broken out across Southern California.
The Lake Fire in Los Angeles County grew to 10,000 acres in less than 4 hours on Wednesday. Overnight Wednesday into Thursday, the fire exhibited explosive and erratic behavior in the form of fire whirls and rapid fire spread. The fire covered 10,000 acres Thursday and was 0 percent contained.
Fortunately the forecast winds over the Lake Fire on Thursday were not expected to be very strong (with gusts up to 15 mph) but low humidity levels and the imminent heatwave will keep the fire threat elevated in the coming days.
And the West isn't the only region dealing with stifling and record-setting heat.
Tens of millions of people are also under heat advisories Thursday across the Central and Southern Plains, including the cities of Oklahoma City, Dallas and Houston. There, high temperatures could reach 100-107 degrees, and those temperatures combined with high humidity will make it feel more like 105-115 degrees. Dallas, Amarillo and El Paso could all set new daily record highs Thursday.
Meanwhile Austin, Texas, is in the middle of a blistering stretch of 100-degree days. The area has recorded 11 straight days of temperatures above 100 degrees with at least five more in the forecast before the streak ends early next week.
The heat and record-breaking temperatures are expected to stay in place through Sunday.