Colorado monsoon season: Burn scars from previous fires present flood concerns in late July

From the Big Thompson Canyon in 1976 to the Poudre Canyon last year, late July is a time for major flash floods in Colorado, and this week, the risk is high once again. 

It's a reality Coloradans have grown accustomed to over the years, as the seasonal warm temperatures meet peak monsoon season. 

"All of these things can come together and mean that you get a lot of precipitation in a very short period of time," said Becky Bolinger, assistant state climatologist at the Colorado Climate Center at Colorado State University.  

While the risk of flooding isn't changing, Bolinger says the destruction left behind, largely in wildfire burn scars, is.  

"These are place that are susceptible to these flash flooding events," she said.  

The Grizzly Creek and Cameron Peak burn scars are two prime examples. Repeated floods there have damaged the interstate, carried away homes, and claimed lives.  

"So, instead of just having rain falling and your typical flooding scenario, now you're having rain falling over an area where the soils can't take in that moisture, and you have a lot of debris," Bolinger said. "So, you're rushing that water all down the surface, and now, you're adding a lot of debris, which is creating the really devastating scenarios that we've seen this year, but also saw last year as well."

They are scenarios that will likely continue for years while some areas recover and others see new fires, partly fueled by a changing climate.  

For now, Bolinger says mitigation efforts such as sandbagging and aerial mulching will be helpful. Being weather aware will too.  

"You want to have your plan and be ready for when an event like that happens," she said. "If you don't live in that area, you say, 'Maybe this is not the day to travel there.'"