About two-thousand people in El Paso have been asked to evacuate because officials fear a dam threatened by heavy rain could burst.
El Paso Mayor John Cook says it would be like a tidal wave hitting the city.
The dam across the border inside Mexico holds back up to six (m) million gallons of water from the rain swollen Rio Grande River, now threatening to burst through the dam.
The El Paso area has been inundated with eight-and-a-half inches of rain this year, almost all of it this week. The rain has caused flash floods and rock slides, and thick mud has poured into homes and covered some roads.