Final surge of monsoon moisture triggers flooding in Phoenix, outside of Las Vegas
Cities across the Desert Southwest receive up to half of their annual precipitation during the monsoon months of June, July, August and September, but these totals can vary dramatically from year to year.
Monsoon weather in Northeast Arizona
FOX Weather Correspondent Robert Ray has been on the move throughout Northeastern Arizona, tracking some noticeable monsoon conditions on Tuesday.
PHOENIX – A late-season surge of monsoonal moisture Friday triggered thunderstorms across the Southwest, which led to flooding across many areas, including Phoenix and outside of Las Vegas.
First responders reported being involved in dozens of water rescues as 1-3 inches of rain fell before the evening commute, causing delays not only on the ground but also in the air around major airports.
At the Phoenix Sky Harbor International Airport, nearly two inches of precipitation fell - surpassing the entire monsoon season's rainfall accumulation.
Officials urged drivers to avoid crossing flooded roadways of unknown depths and said regions along creeks, streams and other low-lying areas were subject to the most significant flash flooding.
Both a Flood Watch and a Flash Flood Warning were in effect into the evening, and most of the state was even under a Severe Thunderstorm Watch - the region's first of the year.
Flooding was reported around Phoenix, Arizona on Friday.
(FOX 10)
RUIDOSO, NEW MEXICO SEES FLASH FLOODING AGAIN AS END OF MONSOON SEASON NEARS
The strongest of the thunderstorms were capable of producing hail and damaging wind gusts, but it was the flooding that appeared to be most consequential.
The Federal Aviation Administration issued ground stops at airports in Phoenix and Las Vegas, where delays were estimated to be running 1-2 hours, with hundreds of flights either being canceled or diverted.
As of Friday evening, there were no reports of missing people associated with the hazardous weather, but the rain was still falling over several areas of Arizona.
Severe Thunderstorm Watch issued for counties in Arizona on 9/26/2025.
(FOX Weather)
Impacts from the flooding remained below the criteria for a Flash Flood Emergency to be issued, which is a more heightened stage of a flash flood alert.
According to NOAA, fewer than 1% of all flood alerts are designated as emergencies and are reserved for catastrophic flooding with life-threatening consequences.
The influx of wet weather likely marked the final stretch of the 2025 monsoon season, which typically fades by late September.
The FOX Forecast Center said scattered rain chances were possible over the weekend before a much drier pattern takes hold next week.
Cities across the Desert Southwest receive up to half of their annual precipitation during the monsoon months of June, July, August and September, but these totals can vary dramatically from year to year.
Shown on the map is the typical weather pattern that dominates during much of the North American monsoon season.
(FOX Weather)