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May 10, 2026 — A rare, destructive storm system pummeled parts of central and northern Arizona with hail up to 3 inches wide, toppled mature trees, and triggered the state’s first tornado watches in more than 15 years.
The National Weather Service issued multiple alerts as intense thunderstorms fired across the region from late Tuesday into Wednesday. Residents were urged to move to interior rooms and stay away from windows as baseball-sized hailstones dented car roofs, shattered glass, and shredded roof shingles. Officials said the unusual setup also carried a real risk of tornadoes and flash flooding.
Communities from Mesa to Flagstaff bore the brunt of the storm’s wind and hail. Wind gusts knocked down large trees, some landing on carports and walls. In the Coconino National Forest, northwest of Flagstaff, at least a few dozen ponderosa pines taller than 30 feet were snapped or toppled.
“These are not small trees that are down,” said Ryan Bernhart, a meteorologist at the National Weather Service office in Flagstaff. “These are pretty strong trees that had been knocked down.”
Residents reported broken windshields and dented siding within minutes of the first hailstones arriving. Some car dealerships and outdoor shopping areas in Mesa looked as though they had been peppered by gunfire, according to local damage photos shared online.
Tornado watches were issued for several parts of the state, a notable event because Arizona had not seen such advisories since Oct. 6, 2010. The timing was especially unusual for meteorologists.
“This is very unusual for this area at this time of the year,” Bernhart said.
Forecasters described the weather pattern as a slow-moving upper-level low pressure system pulling moisture and unstable air into the desert Southwest. Unlike typical summer monsoon thunderstorms, this system had strong wind shear and cool aloft, creating conditions favorable for rotating storms and large hail.
With the severe thunderstorm threat gradually shifting east, forecasters turned their attention to heavy rain. Mark O’Malley, a meteorologist at the National Weather Service office in Phoenix, said rainfall amounts could cause flash flooding across urban areas, especially in the Phoenix metropolitan region.
“Heavy rainfall and potential flash flooding pose the primary hazard tonight and through Thursday morning,” O’Malley said.
Storm drains in low-lying neighborhoods were at risk of being overwhelmed by repeated downpours. The National Weather Service reminded drivers that just a few inches of moving water can sweep a vehicle off the road. “Turn around, don’t drown” was repeated in official briefings.
By the time the storm began to weaken, utility crews were already working to restore scattered power outages. Local emergency management offices advised residents to document any hail damage with photos before contacting their insurance providers. Roof damage may take time to show, officials warned, especially where shingles were punctured but not displaced.
The National Weather Service planned to send damage survey teams to areas where hail and wind reports were most concentrated. Their findings will help determine whether any of the damage was caused by an actual tornado rather than straight-line winds.
In the event of a tornado warning, weather officials urge people to go to the lowest floor of a sturdy building, put as many walls as possible between themselves and the outside, and use pillows or blankets for head protection. Mobile home residents were told to leave immediately and seek shelter in a designated building or community storm shelter.
Severe weather in the desert Southwest can arrive with very little warning. This week’s storm was a reminder that springtime in Arizona is not immune to large, organized thunderstorms. With the threat of flash flooding still active, forecasters advised everyone to monitor local alerts through the rest of the week.
