More than 50 million people across the US are under heat alerts amid a brutal heat wave that has shattered records and caused multiple deaths across the West. As of Monday, much of the West and South are experiencing moderate to major heat risk, the National Weather Service said. California and Nevada are expected to see more daily record high temperatures in the week ahead. By Thursday, the heat in the Pacific Northwest will shift to the Intermountain West and northern High Plains, the National Weather Service's Weather Prediction Center cautions. In Oregon, four people died of suspected heat-related illnesses over the weekend, according to a Monday news release from Multnomah County. Three of the four were residents of Multnomah County, while the other individual was transported from outside the county and later died at a Portland hospital. These deaths happened after the county declared a state of emergency Friday due to "dangerously hot temperatures," but the news release noted "further tests and investigation will determine whether the deaths are officially hot-weather-related. In some cases, the deaths may be found to have had other causes." Dozens of locations in the West and Pacific Northwest tied or broke previous heat records in recent days, and more than 165 daily high temperature records could be tied or broken this week. A motorcyclist died Saturday in California's Death Valley from heat exposure, the Death Valley National Park said in a news release. The high temperature that day was 128 degrees Fahrenheit, according to preliminary data. Six motorcyclists were near Badwater Basin when they became sick due to the heat, the release said. In addition to the cyclist who died, one was transported to a hospital in Las Vegas and the other four were treated on scene. Rescue efforts were hampered due to the extreme heat at the park, as emergency medical flight helicopters cannot fly safely when it is over 120 degrees, the release noted. "Heat illness and injury are cumulative and can build over the course of a day or days," the release said. "Besides not being able to cool down while riding due to high ambient air temperatures, experiencing Death Valley by motorcycle when it is this hot is further challenged by the necessary heavy safety gear worn to reduce injuries during an accident." Heat is the deadliest weather threat in the United States, killing more than twice as many people each year on average than hurricanes and tornadoes combined. Death Valley was among a slew of places where daily temperature records were broken this Fourth of July weekend. On Saturday, Death Valley reached 128 degrees, breaking the daily record of 127 set on July 6, 2007. An excessive heat warning is in effect until late Wednesday evening for the area where temperatures are expected to be between 122 to 129 degrees. On the more-humid East Coast, temperatures above 100 degrees were also widespread, The Associated Press reported. Many areas in Northern California surpassed 110 degrees Sunday, while Phoenix, Arizona, set a new daily record for the warmest low temperature: it never got below 92 degrees. Las Vegas also made history, reaching a record high of 120 degrees on Sunday. Indiana resident Mark Kavacinski told CNN affiliate KVVU his family almost canceled their vacation to Las Vegas because of the intense heat. "We knew it was going to be hot. It's July, right? Did we know it was going to be this hot? No," Kavacinski said. "But we decided that heat's heat. We can handle it." Las Vegas temperatures have exceeded 110 degrees each day since Wednesday and are forecast to do so every day until at least next Sunday, which would mark a stretch of prolonged extreme heat longer than any ever experienced in the city, with 11 days or more above 110 degrees. Sunday's heat was enough to melt crayons, the weather service office in Las Vegas demonstrated on X. And parts of western Nevada and northeastern California won't see temperatures below 100 degrees until next weekend, the National Weather Service office in Reno said. Further north, Oregon's weekend scorcher broke many records. On Sunday, Salem hit 103 degrees, just over the city's 100-degree record from 1945, according to the National Weather Service office in Portland. Eugene also experienced temperatures of 103, breaking the 1945 record of 98 degrees. But some Oregonians told CNN affiliate KATU Sunday they would not miss the Portland Timbers soccer game, regardless of the heat. "Yeah, I know it's hot! It's 100, it's crazy. but the game here is greater," Tim Hueng of Tigard, Oregon told KATU as he waited in line to enter Providence Park. Even mountain destinations couldn't beat the heat. Reno, Nevada, saw a new daily record of 105 degrees on Sunday, the weather service office there announced. And on Monday, Reno reached 106, topping the 2017 record of 104. And despite its elevation of just over 6,000 feet, South Lake Tahoe hit 92 degrees Sunday, beating its daily record of 88 degrees. The high temperatures continued Monday, with the city seeing 91 degrees, breaking 2017's record of 89. — CNN
