Officials reported at least four deaths related to the intense heatwave that got stronger Sunday in the Southwest, NBC News reported.

All four were found dead in Arizona this weekend from separate heat-related emergencies, according to authorities who spoke to NBC News.

A 25-year-old man died while hiking the Peralta Trail in Pinal County on Sunday. In a separate incident, a 28-year-old woman died during a morning hike along the Desert Visa Trail in Maricopa County. Another woman died Sunday at a hospital after hiking in Pima County. And another man died after his hiking group was overcome by heat in Ventana Canyon near Tucson.

Excessive heat warnings blanketed Southern California and Arizona where temperatures jumped into triple digits and are expected to remain there until Monday.

Fire officials said the excessive heat would hamper efforts to quell five explosive wildfires that were forcing evacuations in three states.

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