Heavy monsoonal rains are expected in Southwest Colorado through Tuesday, prompting the National Weather Service to issue an unusual situation report to alert the public and first-responders to be alert for everything from flash floods to rockfalls on highways and roads.
“It was just to give a bit of a heads up to the public emergency managers. We want to keep people in the loop because this is kind of our first real monsoonal setup this year. We want everyone to be aware of the potential for heavy rainfall – you know flash flooding and debris flows especially in the burn scars,” said Mark Miller, a meteorologist with the National Weather Service in Grand Junction.
According to the situation report, excessive rainfall with totals that could exceed 1 inch in spots were expected through Sunday in the San Juan Mountains, particularly east of U.S. Highway 550.
The situation report states the plume of moisture is shifting south and east on Sunday, and leaves slot canyons and burn scars especially vulnerable, mentioning the burn scars from the 416 Fire, the East Canyon Fire and the Lake Christine Fire by name.
Miller expected the heaviest showers in the late afternoon and continuing into the evening.
Lisa Schwantes, a spokeswoman with the Colorado Department of Transportation, said about 4 a.m. Saturday a rockslide closed one lane of traffic on Colorado Highway 145 north of Telluride near Placerville.
“We had a lane that was blocked for about an hour, an hour-and-half. We got a crew out there and were directing traffic, but we’re alerting crews to be ready to respond to rockfalls,” Schwantes said.
In addition, Schwantes said numerous reports of rock falling have come from Red Mountain Pass south of Ouray.
“We want the traveling public to know when we are experiencing these heavy rains, it causes the rock on cliffsides to loosen and fall, and possibly fall into the roadway. Just be aware of your surroundings and slow down,” she said.
Schwartz said motorists can minimize the chances they will be delayed by rockfalls if they can delay travel until two or three hours after rainfalls.
According to the U.S. Geological Survey, a weather measurement station near the Animas River at Tall Timber Resort has received 1.26 inches of rain in the past seven days. The station on the river near the Durango pumping plant has received 0.97 inches in the past seven days. And a station on the river near Cedar Hill, New Mexico, has received 1.45 inches in the past seven days.
Heavy rains, again most likely in the late afternoons into the evening hours, remain a possibility in Southwest Colorado through Tuesday, Miller said.
On Wednesday, a high-pressure system is expected to build over the Four Corners, bringing drier and hotter weather, Miller said.
Isolated and scattered rain showers could still be possible Wednesday and later in the week, but they will likely be confined to the high country, he said.
parmijo@durangoherald.com