The West Coast is preparing for an unprecedented March heat wave, impacting 20 to 25 million people, according to NOAA. The heat will arrive in two waves: the first bringing high temperatures to California, Nevada, Arizona, and New Mexico, and the second extending to Utah, Colorado, Wyoming, Idaho, and Oregon. Temperatures are expected to reach up to 30 degrees above average, potentially breaking monthly records in cities like Salt Lake City, Denver, and Reno.