* WHAT...Dangerously hot conditions with temperatures up to 115 to 118 degrees expected through Death Valley and the lower Colorado River Valley, with highs between 107 to 110 degrees elsewhere.
* WHERE...Portions of northwest Arizona, southeast California, and southern Nevada.
* WHEN...From 10 AM PDT / MST Tuesday to 8 PM PDT / MST Friday.
* IMPACTS...Heat-related illnesses increase significantly during extreme heat events.