* WHAT...Dangerously hot conditions. Afternoon temperatures 109 to 116. Major Heat Risk. Overexposure can cause heat cramps and heat exhaustion to develop and, without intervention, can lead to heat stroke.
* WHERE...In Arizona, Central La Paz, Gila River Valley, Kofa, and Yuma. In California, Chuckwalla Mountains, Imperial County Southeast, and Chiriaco Summit.
* WHEN...Until 8 PM MST /8 PM PDT/ Thursday.
* IMPACTS...Heat related illnesses increase significantly during extreme heat events. Overexposure can cause heat cramps and heat exhaustion to develop and, without intervention, can lead to heat stroke.