Fire and Rain, Colorado Edition

Flames from the High Park Fire west of Ft. Collins in June 2012. US Department of Agriculture

Let our journalists help you make sense of the noise: Subscribe to the Mother Jones Daily newsletter and get a recap of news that matters.


The severe flooding that barreled through the Colorado foothills last week and took at least 8 lives resulted from a freak tempest that’s been deemed one of the worst in the state’s history. In just a few days, Boulder received more than half its normal annual precipitation. It’s quite a reversal from the persistent drought and destructive wildfires Coloradans have recently contended with; in 2010, the Fourmile Canyon fire outside of Boulder became the state’s most destructive to date, until it was surpassed last summer by the High Park and Waldo Canyon fires of 2012, which caused tens of thousands of evacuations along the Front Range. These extreme swings—from parched and burning to flooded—have led some to wonder if climate change is at play; Chris Mooney does a great roundup of the thinking on this in a piece yesterday.

Torrential rainfall, rather than past wildfires, was the biggest factor in Colorado’s flooding.

There’s also been speculation that effects from these recent wildfires could have worsened the flooding: A National Geographic post points to how a lack of vegetation causes denuded hillsides to fail to trap enough water, and Live Science notes that debris slides were spotted in recently burned regions like the High Park Fire area and Boulder’s Fourmile Canyon. There’s good reason to wonder if burn-scarred areas might’ve exacerbated the problem. Wildfires affect soil quality and can increase stream flows and erosion by 10 to 100 times compared to normal forests. Scorched hillsides can send more debris down canyons.

The experts I reached out to with this question agreed that flash floods are often a result of thunderstorms hitting burned areas with repellent soils and lack of vegetation. But most of Colorado’s recent flooding doesn’t exactly fall under this scenario: “Remember that the area that has been burned compared to the area where rain fell is relatively small,” says Lee MacDonald, a hydrology expert at Colorado State University. Some of the rivers that were flooding and causing problems last week, such as in Big Thompson Canyon, weren’t coming out of large burn areas, he says. Instead, the unusual rainfall—deemed “biblical” by the National Weather Service—was the biggest factor in all the runoff.

Wildfires have a large effect on small and medium flooding events, but when rainfall is off the charts, the effect of burned areas shrinks. “It’s going to be difficult to separate out the part of the flooding that was increased because of fire because it was just so much water,” says Kevin Hyde, a post-doc studying post-fire erosion at the University of Wyoming. Proximity could play a role: “the closer you are to the burned areas,” Hyde adds, “the more impact the rainfall has.”

Still, the compounded damages from the cycle of wildfire and flooding could very well be amplified on the Front Range in coming years. Climate models foretell larger regional storms, and scientists have also predicted bigger, more intense wildfires in Colorado’s future. “What is that going to mean for the people living in the mouth of these areas?” wonders Hyde. If the 100-year flood that turned Boulder inside out last week is any indication, living at the base of the Rockies—while arguably worth it—isn’t getting any less complicated.

IT'S NOT THAT WE'RE SCREWED WITHOUT TRUMP:

"It's that we're screwed with or without him if we can't show the public that what we do matters for the long term," writes Mother Jones CEO Monika Bauerlein as she kicks off our drive to raise $350,000 in donations from readers by July 17.

This is a big one for us. It's our first time asking for an outpouring of support since screams of FAKE NEWS and so much of what Trump stood for made everything we do so visceral. Like most newsrooms, we face incredibly hard budget realities, and it's unnerving needing to raise big money when traffic is down.

So, as we ask you to consider supporting our team's journalism, we thought we'd slow down and check in about where Mother Jones is and where we're going after the chaotic last several years. This comparatively slow moment is also an urgent one for Mother Jones: You can read more in "Slow News Is Good News," and if you're able to, please support our team's hard-hitting journalism and help us reach our big $350,000 goal with a donation today.

payment methods

IT'S NOT THAT WE'RE SCREWED WITHOUT TRUMP:

"It's that we're screwed with or without him if we can't show the public that what we do matters for the long term," writes Mother Jones CEO Monika Bauerlein as she kicks off our drive to raise $350,000 in donations from readers by July 17.

This is a big one for us. So, as we ask you to consider supporting our team's journalism, we thought we'd slow down and check in about where Mother Jones is and where we're going after the chaotic last several years. This comparatively slow moment is also an urgent one for Mother Jones: You can read more in "Slow News Is Good News," and if you're able to, please support our team's hard-hitting journalism and help us reach our big $350,000 goal with a donation today.

payment methods

We Recommend

Latest

Sign up for our free newsletter

Subscribe to the Mother Jones Daily to have our top stories delivered directly to your inbox.

Get our award-winning magazine

Save big on a full year of investigations, ideas, and insights.

Subscribe

Support our journalism

Help Mother Jones' reporters dig deep with a tax-deductible donation.

Donate