Arizona Flooding Sparks 'Mass Evacuation' of Duncan

The town of Duncan in southeastern Arizona is under "mass evacuation" after the Gila River overflowed on Monday, reaching a "major flood stage" which prompted authorities to order residents to abandon their homes and seek safety.

The flooding of the river—a 649-mile long tributary to the Colorado River flowing through New Mexico and Arizona—was caused by heavy monsoon rainfall and storms on August 22.

"At approximately 4:30 this morning the water levels of the Gila River reached a point where water began to spill into portions of Duncan," the Duncan Valley Rural Fire District wrote on Facebook. "Currently the water level at the bridge is 22.27', which is classified as a major flood stage."

Already on Sunday night, the Gila River had crested a record 30.28 feet in New Mexico's Virden—a town 7 miles east of Duncan—according to the National Weather Service (NWS).

By Monday afternoon, the river had covered flood prone parts of the town, which can be seen in images and footage shared on social media completely underwater.

More than a dozen of streets in the 712-person town are being evacuated.

The Greenlee County Fairgrounds is being used as an evacuation center, while anyone who needs to move livestock can use the corrals at the Fairgrounds, according to the Duncan Valley Rural Fire District.

Several flood warnings were raised by the Tucson branch of the NWS over the Gila River and its tributaries, valid until 9 a.m. on Tuesday for Greenlee County and 8 p.m. for Graham County, raising the alert over the threat of flooding of urban areas, highways, streets and underpasses.

Flash flooding isn't unusual in this area of Arizona at this time of the year, but the one on Monday was different.

The area surrounding Duncan experienced a lot of rain in the past week, "and the ground is saturated so it is draining into creeks, canyons and washes downstream to the river, making the river water level rise," explained the Duncan Valley Rural Fire District on Facebook.

Nearly all of Arizona and New Mexico have been under flood watches in the past few days, as moisture brought from the seasonal monsoon increased the risk of flash floods and other hazards.

The risk of floods has been made higher by the drought conditions the southwest has experienced in the past 23 years, with the ground now being so dry that it's unable to absorb the heavy rain suddenly falling. Experts believe the mega-drought and the unusually heavy downpours this year are linked to climate change.

Federal forecasters expect rain to continue in the coming days in areas from Arizona to Texas.