Portions of northern Arizona are under an excessive heat warning Thursday as hot temperatures scorch the Southwest.
The National Weather Service says elevations of 4,000 feet and below can expect temperatures between 105 and 111 degrees. That includes parts of Yavapai County, the Verde Valley, lower elevations of the Grand Canyon and Marble and Glen canyons.
The warning is in effect through Friday evening.
At the Grand Canyon, park officials are urging visitors not to hike below the rim during the heat wave. Areas like Phantom Ranch and Havasupai Gardens could see highs up to 111 degrees — even in the shade.
Officials warn hiking in extreme heat can lead to serious health risks ranging from heat exhaustion to heat stroke or even death.
Anyone who does attempt to hike in the canyon should do so before 10 a.m. and after 4 p.m. and remain in the shade the rest of the time.
Day hikers on the Bright Angel Trail shouldn’t pass the 1.5-mile Resthouse. Both the South and North Rims will also see high temperatures in the coming days.
Visitors should stay hydrated, dress appropriately and watch for signs of heat stroke like fainting and confusion.