COCONINO COUNTY — The National Weather Service in Flagstaff issued and extended multiple flash flood warnings across Coconino County on Wednesday, July 15, 2026, as thunderstorms dumped heavy rain on vulnerable desert terrain, triggering dangerous flooding in Havasu Creek, Antelope Creek, and Rock Canyon. The warnings covered some of Arizona’s most iconic and heavily visited natural areas, including the Havasupai Reservation and Antelope Canyon, and urged immediate action from residents and visitors due to life-threatening conditions.

The National Weather Service in Flagstaff extended a Flash Flood Warning for the Havasu Creek basin in Coconino County until 10 p.m. MST on Wednesday, July 15. By 7:02 p.m.

MST, local law enforcement reported a 6 to 8 foot flood wave moving down Havasu Creek, after between 0.5 and 1 inch of rain had fallen in the basin. The warning included the Colorado River between river miles 156 and 158, as well as specific locations such as Little Navajo Falls, Mooney Falls, Beaver Falls, the Havasupai Reservation, Supai, and Hualapai Hilltop.

Separately, the National Weather Service issued a Flash Flood Warning for the Antelope Creek basin in Coconino County until 7 p.m. MST on the same day. At 4:02 p.m.

MST, Doppler radar detected thunderstorms producing heavy rain over the basin, where between 0.75 and 1 inch of rain had already fallen. Forecasters noted that additional rainfall amounts of 0.25 to 0.5 inches remained possible in the warned area. The Antelope Creek warning encompassed LeChee and Antelope Canyon, along with Upper Antelope Canyon, Lower Antelope Canyon, Canyon X, Cardiac Canyon, Owl Canyon, Rattlesnake Canyon, Mountain Sheep Canyon, Ramshead Canyon, Wind Pebble Canyon, Porcupine Canyon, Antelope Creek, Water Holes Canyon, and Honey Draw.

The agency also issued a Flash Flood Warning for Rock Canyon in Coconino County on Wednesday, July 15. A meteorologist with the National Weather Service described the situation as dire, stating, "This is a life threatening situation. Heavy rainfall will cause extensive and severe flash flooding of creeks, streams, and Ditches in the Rock Canyon.

Severe debris flows can also be anticipated across roads. Roads and driveways may be washed away in places. If you encounter flood waters, climb To safety."

Flash floods occur when heavy or excessive rainfall accumulates in less than six hours, rapidly overwhelming dry or burn-scarred landscapes that cannot absorb the water. In such conditions, even shallow water poses extreme danger: just 6 inches of moving floodwater can sweep a person off their feet, 12 inches can carry away smaller vehicles, and two feet of water is enough to move SUVs and trucks.

Coconino County, the second-largest county by area in the United States and home to numerous recreation sites and Indigenous communities, is especially vulnerable to flash flooding during summer monsoon season. The July 15 warnings affected some of the region’s most visited natural landmarks—areas where thousands of tourists hike narrow slot canyons annually. The Havasupai Reservation, accessible only by foot, horse, or helicopter, and Antelope Canyon, a major tourism draw near Page, Arizona, both require timely evacuations during flood threats due to limited escape routes. The National Weather Service’s rapid warnings and specific location details are critical for public safety in these remote and high-risk zones.