A tornado warning was issued by the National Weather Service (NWS) Flagstaff for parts of Coconino County, Arizona, on Wednesday, October 21. The warning was in effect from 5:49 AM MST until 6:15 AM MST on that day.

At 5:49 AM MST, a severe thunderstorm capable of producing a tornado was located near Fort Valley. This location is approximately 11 miles northwest of Flagstaff. The storm was moving northeast at 35 miles per hour. The NWS identified the hazards as a tornado and quarter-sized hail. This assessment was based on radar-indicated rotation within the storm.

The NWS warned that flying debris would be dangerous to those caught without shelter. Mobile homes were likely to be damaged or destroyed. Damage to roofs, windows, and vehicles was also expected. Tree damage was considered likely as well.

Areas specifically impacted by the warning included Fort Valley, Arizona Snowbowl, Saddle Mountain, Kachina Peaks Wilderness, Lava River Cave, and Wing Mountain. The warning also covered U.S. Highway 89 near mile marker 435 and Highway 180 between mile markers 227 and 240.

This localized tornado warning occurred as much of Arizona was under a "flood watch" starting Wednesday. The National Weather Service issued a flood advisory for the northern region of Arizona, effective from Wednesday morning through Thursday evening. Starting around 6 AM on October 21, areas such as Flagstaff, Sedona, Camp Verde, and Tuba City had a high probability for precipitation that was expected to continue into Thursday. Official weather advisories and alerts are regularly issued for Coconino County. Coconino County also uses an emergency notification system to send real-time alerts to the public about life-saving actions.