Heat dome brings extreme heat to western US and Canada

An unusually intense and widespread heat dome is bringing dangerously high temperatures to the western United States and parts of Canada, placing tens of millions under heat alerts as the system settles in for an extended stay. The heat wave, which began in late July, reached a peak intensity over the weekend of August 1-2, threatening dozens of daily records and making this period the hottest of the year so far for many areas.

Approximately 40 million people across the western U.S. are under some form of heat advisory or warning, with the most severe conditions centered on the Desert Southwest. More than 12 million people across the Southwest, Mountain West, and northern Great Plains faced an "extreme" heat risk, the highest level of warning, on Saturday and Sunday. The National Weather Service has warned that heat at this level can affect anyone without access to adequate cooling and hydration.

Major cities enduring dangerous highs include Phoenix, Las Vegas, and Los Angeles, where officials have urged residents to avoid the sun during peak hours. Death Valley, California, was forecast to reach a blistering 126 degrees Fahrenheit on Saturday. However, some of the most...