Record temperatures have been shattered from Palm Springs to Las Vegas. A dangerous and unprecedented heat wave is hitting the West, with temperatures reaching 25-to-40 degrees above normal across the region. A dozen cities recorded all-time record March temperatures on Wednesday, including 105 degrees in Palm Springs, California; 102 degrees in Phoenix, Arizona; and 94 degrees in Las Vegas. Heat alerts are in place for 40 million Americans in the West through the weekend. With temperatures expected to reach between 96 and 109 degrees for a widespread area over multiple days -- and during a time of high tourism to the Desert Southwest -- the heat may turn deadly. The heat will spread east through the week. By Friday, the record highs may reach Texas, Nebraska and Oklahoma, and by Sunday, daily record highs could stretch from Los Angeles to Memphis, Tennessee. The heat and dry weather could also increase the risk of wildfires.…