Evelin Ruelas/Cronkite News

“Take a Hike, Do it Right” signs warns visitors of the dangers while hiking in hot conditions.

Maricopa County is under an excessive heat warning through Monday.

Phoenix has seen 11 consecutive days above 110 degrees and is poised for yet another.

Health experts are warning that heat-associated illness is likely to be more common.

Symptoms of heat exhaustion include heavy sweating, weakness, headaches, dizziness and vomiting.

If not addressed, It can lead to the more severe and deadly heat stroke.

That can lead to a rapid strong pulse, confusion, fainting and loss of consciousness with a body temperature above 103 degrees.

The CDC says it’s important to call 911 if someone shows signs of heat stroke.

Thunderstorms that can bring relief have been delayed due to the El Niño weather pattern in the Pacific.

Sam Meltzer with the National Weather Service says conditions could be abnormally dry in the Southwest.