A flash flood watch for parts of Southwest Colorado and southeast Utah has been issued by the National Weather Service until midnight tonight.
The watch area encompasses Montezuma County, Ute Mountain Ute tribe, Dolores County, San Miguel County, northern La Plata County, northern and eastern Archuleta County, San Juan County, western Montrose County and San Juan County, Utah.
Monsoonal rains might cause flooding in the cities of Cortez, Mancos, Dove Creek, Ridgway, Gateway, Glade Park and Nucla.
Other areas susceptible to flooding during the watch period are the upper and lower Dolores River, Dallas Divide, Four Corners, Paradox Valley and Uncompahgre Plateau.
“A flash flood watch means conditions are favorable for flash flooding to potentially occur,” said Jim Andrus, National Weather Service observer for Cortez.
According to the National Weather Service, monsoonal moisture remains entrenched over portions of Southwest Colorado. This will lead to multiple rounds of afternoon thunderstorms capable of producing heavy rainfall.
“Several areas have received heavy rainfall the past few days, and additional amounts could lead to excess runoff and localized flash flooding,” the weather service forecast stated. “Rainfall amounts of a half to one inch in a short duration will exacerbate flooding concerns in the watch area.”
The weather service said the public should monitor later forecasts and be prepared to take action should flash flood warnings be issued, which means flash flooding is imminent or occurring.
Showers and thunderstorms will become more widespread Thursday, the weather service said, beginning over the high terrain by late morning and drifting into lower elevations late afternoon into the evening. Lightning and heavy rainfall will be the main threats along with gusty outflow winds and hail in the stronger storms.
As of Tuesday, Durango had recorded 2.58 inches of rain for July compared with 1.6 inches for all of July 2020. July’s average rainfall in Durango is 1.72 inches.
Rainfall total for Cortez in July is at 1.43 inches, or 112% of the average of 1.28 inches.
June saw 0.52 inches of rain, which is 130% of the monthly average of 0.40 inches.
“That makes two months in a row for above-normal rainfall,” Andrus said. “We are in an irregular monsoon pattern where storms are coming from all different directions, including the classic southwest pattern.”
Year-to-date precipitation for Cortez is at 5.5 inches, which is 88% of the average of 6.30 inches by this time of year.
The recent rains have lowered the drought level in the mountainous areas of Montezuma and La Plata counties from the severe drought level to moderate drought conditions.
The recent rains increased the Dolores River flows at Dolores to 350 cubic feet per second July 29 in the early morning, up from 150 cfs on July 22, according to the U.S. Geological Survey gauge. On July 25, the river ran over 400 cfs at Dolores.