The National Weather Service in Flagstaff extended a flash flood warning for the Havasu Creek basin in Coconino County, Arizona, until 5 a.m. MST Monday, the agency said. At 10:52 p.m. MST, heavy rain had ended, but 0.5 to 1.5 inches had already fallen and flash flooding was ongoing, according to the warning. The weather service described the hazard as life threatening and said radar indicated the flooding.
KEY FACTS
- The warning covers Little Navajo Falls, Mooney Falls, Beaver Falls, Hualapai Hilltop, the Havasupai Reservation and Supai, the weather service said.
- It also includes the Colorado River between river miles 156 and 158 and all swimming holes on Havasu Creek near Supai.
- The weather service listed Havasu Creek, Sinyella Canyon, Heather Wash, Pasture Wash, Little Coyote Canyon and Black Tank Wash among affected waterways.
- The agency said heavy rain had ended but warned that flash flooding remained ongoing.
CONTEXT
The National Weather Service issued the extension at 10:52 p.m. MST on September 13, replacing an earlier warning that had been set to expire. The warning is based on radar estimates, not direct river gauge observations, and covers a rugged section of the Grand Canyon region where travel is largely by foot, mule or boat. Havasu Creek flows through the Havasupai Reservation before joining the Colorado River. The affected stretch of the Colorado River lies between river miles 156 and 158, a corridor used by river runners. The weather service did not report injuries, evacuations or structural damage in the warning text. Flash flooding in narrow canyons can rise quickly and carry debris, and the agency classifies the hazard as life threatening.
WHY IT MATTERS
The warning affects a remote area where visitors and residents have limited escape routes and communication. Supai, the main village in the Havasupai Reservation, is reachable only by an 8 mile trail, helicopter or horse, so fast moving water can isolate people before outside help arrives. The Colorado River corridor between miles 156 and 158 is also used by commercial and private boaters who may camp near the mouth of Havasu Creek. Because the warning relies on radar rather than on the ground gauges, conditions can change without immediate confirmation.
WHAT TO WATCH
- Whether the National Weather Service extends, cancels or expands the warning before 5 a.m. MST Monday.
- Any reports from the Havasupai Reservation, Supai or river runners about flooding impacts or rescues.
- Whether the Colorado River corridor between miles 156 and 158 remains passable for boaters.
- Any updated rainfall estimates or new warnings for Coconino County.