 Officials say one visited to the park died Saturday from heat exposure, and another person was hospitalized. But you don't have to visit the desert to be exposed to the extreme heat. In Multnomah County, Oregon, Dr. Richard Bruno of the County Health Department says they're investigating at least four deaths that are suspected to have been caused by the heat. More than 146 million people around the U.S. were under heat alerts Monday, especially in western states.