The National Weather Service Tucson issued a Flash Flood Warning for Oro Valley, Casas Adobes and Marana on Sunday, Nov. 1, after heavy rain triggered life-threatening flooding across the area.

The warning was initially set to expire at 1:45 p.m. MST but was extended by the National WeatherServiceuntil 3:45 p.m. MST as runoff continued and area washes remained active. It covered northeastern Pima County and south-central Pinal County, an area that includes about 466,142 people, 156 schools and eight hospitals, according to NWS flash flood impact data.

Between 1 and 2 inches of rain had fallen by 10:52 a.m. MST, with up to 1 additional inch possible, the NWS said in its warning bulletin. Doppler radar and automated rain gauges confirmed the heavy rainfall.

Multiple swift water rescues were reported.


The NWS rated the flash flood damage threat as "considerable" and warned of life-threatening flooding on creeks, streams, highways, streets and underpasses. The agency urged residents to move to higher ground and avoid walking or driving through flood waters.

"Turn around, don't drown when encountering flooded roads," the NWS stated in its warning. "Most flood deaths occur in vehicles."

Where flooding is expected

The warning listed several flood-prone locations in and near Oro Valley, including Overton Road at Canada del Oro and E. Wilds Road at the Canada del Oro. Other spots include Twin Peaks Road between Sanders and Sandario, Silverbell Road near Ina Road and Camino De La Tierra at the Rillito River.

Affected waterways include the Canada del Oro, Rillito River, Santa Cruz River, Sutherland Wash, Big Wash and Alambre Wash, among others.

Catalina Foothills was also listed among communities expected to experience flash flooding, along with Tucson, Catalina, Marana, Oracle, Saddlebrooke and South Tucson.

Flood watch extends through Sunday night

A broader Flood Watch also remained in effect through late Sunday night across southeast Arizona. The NWS had forecast the storm system on Oct. 31, projecting widespread valley rainfall of 0.5 to 1.75 inches and mountain totals of 1 to 3 inches or more.

The Flood Watch warned that excessive runoff could flood rivers, creeks, low-water crossings and urban areas.