Much-awaited rain on the way in Colorado this weekend is expected to help ease drought, and it could help clear polluted air.
Colorado health officials have issued an ozone alert as air quality deteriorated along the northern Front Range cities — the seventh alert this year.
National Weather Service officials on Thursday also pointed out the possibility of flooding and slides as storms pass over burn scars. They stopped short of issuing a flood warning, deeming the threat limited depending on how fast rain storms roll eastward.
Fires have left more than 36 burn scars across western Colorado covering more than 700 square miles. Landscapes ravaged by the 2020 Cameron and East Troublesome fires northwest of Denver, in particular, “cannot absorb as much water,” weather service meteorologist Caitlyn Mensch said. “So there’s runoff, and debris could be an issue if there’s flash flooding.”
Summer monsoon rain was forecasted over western Colorado between Thursday afternoon and Sunday, spreading east of the mountains to the high plains.
“There’s going to be plenty of rain storms around. But they’ll be moving at a decent enough pace that they’re probably not going to be sitting over those burn scar areas,” Mensch said.
The meteorologists predicted up to a half-inch of rain overall in mountainous parts of western Colorado and around a quarter inch along the Front Range.
Colorado typically receives less than 14 inches of rain a year across its semi-arid landscapes.
Federal drought monitors show most of western Colorado “abnormally dry” and classified the eastern plains in severe drought.
“This is definitely much-needed moisture that we will get in the mountains. The further you go east, the smaller amounts you will get,” Mensch said.
Any rain could help clear the air.
The Colorado Department of Public Health and the Environment issued an alert and requested reduced driving of gas or diesel-powered vehicles Thursday as ozone concentrations reached levels deemed unhealthy for children, the elderly and residents with lung ailments such as asthma. Health officials advised these sensitive groups to avoid exertion outdoors.
Colorado Front Range urban air has exceeded the federal ozone pollution health limit of 70 parts per billion on at least seven days this year, according to Regional Air Quality Council data. In 2021, the data show ozone exceeded 75 ppb on 48 days.