Golf-Ball Hail Hits Arizona as Storms Damage Homes and Raise Flood Risk

Golf-ball-size hail hit Flagstaff, falling trees damaged homes and vehicles, and a possible tornado tore through a mountain community as an unusually violent October storm swept across Arizona. By Thursday morning, residents in several parts of the state were assessing the damage while more heavy rain remained in the forecast.

The worst reported destruction overnight was in Heber-Overgaard, a community of about 3,000 people northeast of Phoenix. A storm that prompted a tornado warning uprooted trees, knocked down utility poles and damaged buildings. The Navajo County Sheriff’s Office reported property damage and minor injuries. A tornado touchdown had not been officially confirmed Thursday morning.

At Overgaard Baptist Church, members had gathered for a prayer meeting when the storm arrived. They sheltered inside as trees, signs and fences fell and windows broke. Nobody at the church was reported hurt.

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Across northern Arizona on Wednesday, hail measured as large as 1.75 inches — roughly the size of golf balls — struck parts of Flagstaff. Elsewhere, severe winds sent trees onto walls and carports in Mesa and uprooted dozens of large ponderosa pines in the Coconino National Forest. The damage extended from mountain communities into the Phoenix metropolitan area, where flooded streets and downed lines posed additional problems.

Why October produced tornado warnings

Arizona has familiar summer thunderstorms, but the combination of large hail, destructive wind and tornado conditions in late October was unusual. Tornado watches were issued in parts of the state for the first time since October 2010.

A strong low-pressure system approaching from the Pacific drew tropical and subtropical moisture inland. At the same time, changing winds at different heights helped some thunderstorms develop rotation. That mix brought the possibility of tornadoes to places where they are uncommon, alongside damaging hail and heavy rain.

The distinction between a tornado warning and a confirmed tornado matters. Warnings can be issued when radar detects storm rotation capable of producing one; a National Weather Service damage survey or direct evidence is needed to establish what actually touched down. The damage in Heber-Overgaard was still being evaluated.

Flooding remains a danger even after the hail

The storm system was not finished Thursday. The National Weather Service in Flagstaff warned that total rainfall of 1 to 3 inches was possible across parts of northern Arizona, with locally higher amounts, and kept a flood watch in place through Thursday evening.

Rainfall of that magnitude can be particularly dangerous in the Southwest. Normally dry washes can fill quickly, low-water road crossings can become impassable, and slopes scarred by wildfires can send mud and debris downhill. Flooding can develop well away from the heaviest-looking storm.

Residents were urged to monitor local National Weather Service alerts, stay clear of damaged power lines and avoid driving across water-covered roads. A flood watch signals that flooding is possible; a flash-flood warning means dangerous flooding is occurring or imminent.

Forecasters expected the storm threat to shift eastward across Arizona Thursday before drier weather returned toward the weekend. The damage already visible in Flagstaff, Mesa and Heber-Overgaard showed how rapidly a powerful storm can disrupt communities far beyond the desert’s usual summer thunderstorm season.