Flood Watch for Southeast Arizona
A Flood Watch is in effect across portions of Southeast Arizona through late tonight, as an influx of tropical moisture combines with afternoon and evening thunderstorms to create a heightened risk of flash flooding.
The National Weather Service in Tucson issued the watch Thursday morning for the Catalina and Rincon Mountains; Dragoon, Mule, Huachuca and Santa Rita Mountains; Tucson Metro Area; Upper San Pedro River Valley; and Upper Santa Cruz River Valley/Altar Valley. The watch is scheduled to remain in effect through late tonight. (National Weather Service)
Forecasters expect scattered to numerous thunderstorms during the afternoon and evening. Rainfall totals could reach 1 to 1.5 inches, with localized amounts of 2 inches or more possible. Areas that have already received substantial rainfall during the past 48 hours may be particularly vulnerable to rapid runoff and flash flooding. (National Weather Service)
Why Flash Flooding Is a Concern
Southeast Arizona’s monsoon environment can produce intense rainfall over a relatively short period. When thunderstorms repeatedly develop over the same area, rainfall can quickly overwhelm washes, creeks, drainage systems and low-water crossings.
The National Weather Service notes that excessive runoff could produce flooding in rivers, creeks, streams, low-lying areas, poor-drainage locations and urban areas. Low-water crossings are also vulnerable. (National Weather Service)
Additionally, recent rainfall means some locations may experience faster responses in washes and drainage channels even when storms are occurring several miles away.
Areas Included in the Flood Watch
Catalina and Rincon Mountains
Mountain communities, including Mount Lemmon and Summerhaven, could experience periods of heavy rain and rapid runoff. Steep terrain can accelerate water movement through normally dry channels and washes.
Dragoon, Mule, Huachuca and Santa Rita Mountains
Thunderstorms across southeastern Arizona’s mountain ranges may produce locally intense rainfall. Communities and travelers near Bisbee, Canelo Hills and Madera Canyon should remain alert for rapidly changing conditions. (National Weather Service)
Tucson Metro Area
The Tucson Metro Area, including Tucson, Marana, Vail and Green Valley, remains vulnerable to urban flooding when thunderstorms produce heavy rainfall.
Stormwater can accumulate quickly on roadways, underpasses and areas with poor drainage.
Upper San Pedro River Valley
The Upper San Pedro River Valley, including communities such as Sierra Vista and Benson, is also included in the watch.
Thunderstorms could generate runoff into normally dry washes and waterways, creating hazardous conditions even after the heaviest rainfall has moved away.
Upper Santa Cruz River Valley and Altar Valley
The watch also covers the Upper Santa Cruz River Valley/Altar Valley, including areas around Nogales.
Recent weather has already demonstrated the region’s potential for rapid flooding. On September 2, the National Weather Service issued a Flash Flood Warning in southeastern Santa Cruz County after thunderstorms produced approximately 1 to 1.5 inches of rain. (National Weather Service)
Graham County Power Outage Concerns
Graham County residents should also keep an eye on local power conditions as thunderstorms move through southeastern Arizona.
As of the latest outage information reviewed for this report, the available utility outage data did not show a significant active outage in Graham County. However, outage conditions can change quickly during thunderstorms, particularly if strong winds, lightning or falling trees damage electrical infrastructure. (PowerOutage.com)
Residents experiencing an outage should report it directly to their electric provider and avoid downed power lines.
Flash Flood Safety: Turn Around, Don’t Drown
Flooded roads can become extremely dangerous, even when water appears shallow.
Never drive through a flooded roadway. Water can hide washed-out pavement, debris and dangerous currents. The National Weather Service repeatedly emphasizes the importance of turning around rather than attempting to cross flooded roads. (National Weather Service)
Keep these safety steps in mind:
- Never drive around barricades or road closures.
- Avoid low-water crossings during and immediately after heavy rain.
- Move to higher ground if water begins rising around your location.
- Stay away from flowing water near washes, creeks and rivers.
- Do not walk or drive through moving floodwater.
- Monitor weather alerts throughout the afternoon and evening.
- Be prepared to act quickly if a Flash Flood Warning is issued.
More Storms Could Develop Through the Weekend
The threat is not limited to Thursday. The National Weather Service expects scattered to numerous thunderstorms each afternoon and evening through the weekend as tropical moisture continues moving into the region. Heavy rainfall and flash flooding are expected to remain the primary weather concerns. (National Weather Service)
That means saturated or recently soaked areas may remain especially vulnerable to additional rainfall.
Radar Watch HQ Final Thoughts
Southeast Arizona is entering another potentially active period of monsoon thunderstorms, with heavy rainfall and flash flooding remaining the biggest concerns.
If you live in or travel through the Tucson Metro Area, surrounding mountain ranges, Upper San Pedro River Valley or Upper Santa Cruz River Valley/Altar Valley, stay weather-aware through tonight. A sunny or quiet period does not necessarily mean flooding cannot occur nearby—thunderstorms can produce intense rainfall and rapid runoff in a short amount of time.
Remember: Turn around, don’t drown. If a Flash Flood Warning is issued for your location, take immediate action and move to safer, higher ground.
Stay weather-aware. Stay prepared. Stay safe with Radar Watch HQ.
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Radar Watch HQ Top 5 Essential Emergency Preparedness Picks
Whether you’re preparing for severe thunderstorms, flash flooding, hurricanes, wildfires, or extended power outages, these five emergency essentials can help keep your household safer when severe weather strikes.
A portable power station provides reliable backup electricity during outages, allowing you to power phones, medical devices, laptops, lights, small appliances, and communication equipment without fuel.
Best for:
- Extended power outages
- Severe thunderstorms
- Hurricanes
- Winter storms
- Wildfires
2. Flood Protection Barriers & Sandless Flood Bags
Flood barriers help divert or absorb water before it enters garages, doorways, and low-lying areas. They deploy quickly and can help reduce property damage during flash flooding.
Best for:
- Flash Flood Warnings
- Heavy rainfall
- River flooding
- Coastal flooding
3. Rechargeable LED Flashlights
Bright, dependable flashlights are essential when the power goes out. Rechargeable or solar-powered models provide long-lasting illumination for navigating safely indoors and outdoors.
Best for:
- Overnight power outages
- Emergency evacuations
- Storm damage inspections
Keep phones, tablets, weather radios, and USB-powered devices charged when the electrical grid is unavailable. A solar power bank offers an additional charging option during prolonged emergencies.
Best for:
- Communication during outages
- Emergency weather alerts
- Travel and evacuation
A NOAA Weather Radio delivers official weather alerts directly from the National Weather Service, even when cellular networks or internet service are unavailable. It remains one of the most dependable ways to receive life-saving warnings.
Best for:
- Tornado warnings
- Severe thunderstorm warnings
- Flash flood warnings
- Hurricane alerts
- Winter storm emergencies
Why Radar Watch HQ Recommends These Essentials
At Radar Watch HQ, preparedness is just as important as staying informed. These five emergency essentials can help you stay connected, protect your property, and safely navigate severe weather events. Having supplies ready before storms arrive allows you to respond quickly when warnings are issued and conditions begin to deteriorate.
