Heavy storm system hits Arizona Valley with flash flood and severe thunderstorm warnings

A powerful storm system moved through parts of the Arizona Valley on September 26, 2025, bringing heavy rain, lightning, and a major cool down as a weather shift took hold. The storm has prompted multiple flash flood warnings and severe thunderstorm alerts across various cities and counties, causing heightened safety concerns and disruptions.

At 10:22 am MST, the National Weather Service (NWS) in Phoenix issued a Flash Flood Warning extended until 1:30 pm MST for Glendale, Peoria, and Surprise. The warning highlighted the risk of sudden runoff and dangerous flooding conditions in low-lying areas.

Concurrently, severe thunderstorm warnings were announced by NWS Flagstaff covering Yavapai County areas including Congress, Peeples Valley, Hawkins, Piedmont, Walnut Grove, and Yarnell, effective until 10:45 a.m. MST. Additionally, warnings were in place for Wittmann and Beardsley until 10:30 a.m. MST.


Observers reported steady rain beginning early in the morning, with reminders from the Arizona Department of Transportation (DOT) emphasizing cautious driving. Drivers were advised to check windshield wipers, slow down to maintain extra braking distance, and avoid driving into water pooling on streets to prevent hydroplaning or vehicle stalling.

Traffic information was actively updated, and the AZ511 app was recommended by Arizona DOT for real-time updates, available on both Apple and Android devices.

The storm system marks a stark contrast to previous conditions, bringing a welcomed but challenging cool-down. Residents should stay tuned to local updates and heed all weather warnings to ensure safety until the storm system passes.

FAQ:

Q: What should residents do during a flash flood warning?
A: Residents should avoid low-lying flood-prone areas, not attempt to drive through flooded roads, move to higher ground if necessary, and stay informed through official channels.

Q: How long will the severe warnings last?
A: Warnings vary by location but some were in effect until around early afternoon on September 26. Check NWS updates for specific local duration.

Q: Is this storm part of a larger weather pattern?
A: Yes, it is linked to a broader weather system causing wind, rain, and cooler temperatures across the region.