There is a possibility that a dam on the Tohono O’odham Nation may overflow and could fail due to heavy rain and flooding from remnants of Tropical Storm Rosa, authorities said Tuesday night.
The status of the dam remained unchanged on Wednesday morning, weather officials said. There is flooding in the area, but officials are unsure if it's from the dam.
A flash flood warning is still in place for Ali Chuk.
The reservation’s Office of Emergency Management and its Police Department were working on evacuations, a Tohono O’odham Nation representative said on Tuesday. A number of shelters were made available to evacuees.
Border Patrol agents also helped with evacuations.
Here is a look at the 72 hour estimated precipitation in the Menegers Lake area of the T.O. nation where dam overtopping and/or failure is imminent. Widespread 3-5" in the area with isolated 5 to 7" upstream to the NW. #azwxpic.twitter.com/4gnUGhz90W
The National Weather Service in Tucson tweeted: “Dam failure is imminent” at Menager Lake and Menagers Dam.
Both are in the Gu Vo District on the southwest corner of the reservation, in Pima County and close to the U.S.-Mexico border. They are west and southwest of Sells, which is about 60 miles southwest of Tucson.
An alert issued by the weather service on Tuesday said:
“If the dam is overtopped, which appears likely, the dam could give way, resulting in rapid flash flooding of the town of Ali Chuk and surrounding area as the floodwaters rush toward the Mexican border. Flash flooding is expected to begin shortly and immediate evacuation of the Ali Chuk area is strongly advised per Tohono O’odham Nation authorities.”
Certain areas of the reservation have received up to 7 inches of rain within 72 hours, and rain levels of 3 to 5 inches are widespread on the reservation, said Glenn Lader, a meteorologist with the weather service in Tucson.
He said Menagers Dam is an old earthen dam that’s 22 feet high.