Scientists at Colorado State University and elsewhere in the West are poking and prodding for clues into how wildfire impacts water supply.
May 6, 2022
CAMERON PASS — On a cloudy morning in April, not far from the summit of Cameron Pass, Megan Sears drops a pair of snowshoes onto the shoulder of Highway 14, 60 miles west of Fort Collins
Sears, a graduate student studying watershed science at Colorado State University, cinches the binding straps tight onto her snow boots. She tucks a scientific instrument that looks something like a giant telescope made of clear plastic under her shoulder and starts walking up a snowy hill into what remains of the forest burned nearly two years ago by the largest wildlife in Colorado history.
In a state where every drop of water matters, Sears and another grad student, Mikaela Richardson, are out collecting data that will help answer an important question that’s gaining more attention from the scientific community: If massive wildfires continue to spread across the West, particularly at higher altitudes where snowpack is more plentiful and critical, what effect will that have on the region’s water supply? “How is this fire and the impact from it changing the hydrologic regime of this area?” Sears says as she treks through the snow. “And what does that mean for, you know, the Poudre River?”
The past two years, beginning around December and continuing through May or June, Sears and other CSU researchers have walked to various points in this burned forest to measure both the snow depth and the amount of water held in the snow. The telescope-looking instrument measures SWE, or snow water equivalent. The device can remove a core sample from the snowpack; Sears and Richardson can then weigh the sample and calculate the water content in the snow. After gathering this data, for comparison, Sears and Richardson will do the same thing in a nearby area spared by the Cameron Peak fire.
Often, post-fire concerns focus on potential challenges with water quality, which can be impacted by sediment and debris more easily running down a barren hillside. But the work Sears and Richardson are doing, sampling snow in the middle of a scorched forest that burned as high as 11,915 feet, aims to get at something else: Will the ecosystem left behind by wildfires translate to more or less water in rivers and streams?
“I’m really curious,” Sears says, “how this impacts the snowpack.”
A different view
In August of 2020, when Stephanie Kampf, a professor in the department of ecosystem science and sustainability at Colorado State University, spotted the early plumes of smoke rising out of the Arapaho and Roosevelt National Forests west of Fort Collins, she began to follow the fire with a scientific curiosity.
Kampft noted a few things in particular. The first was that the fire — the origin of which is still under investigation but is suspected to be human-caused — was burning at a high elevation, places where snowpack builds and persists through the winter. The second thing was that even though the fire was burning high up it appeared to be spreading rapidly, an unusual combination. “It started growing in ways that were surprising,” Kampf said. “It had covered a larger high elevation area than we had seen burn here before.”
Eventually, Kampf, who studies hydrology and how runoff is affected by climate, started to think about how she might exploit this disaster in the name of research. She wrote a proposal to collect data on how the fire could impact “snowpack, streamflow, slope failures, stream channels, and water supply reservoirs,” and received a $50,000 grant from the National Science Foundation to get started. “It seemed that we would be able to address this water supply question,” Kampf said.
Further west, Kelly Gleason, an assistant professor in the department of environmental science and management at Portland State University, fell in love with this work back in 2010. Gleason loves to ski and burned forests happen to make for pretty good skiing, she said. Gleason was out one day carving turns in a nicely gladed burned area. She found herself thinking about the charred bits of tree branches, twigs and trunk scattered on the snow, when she experienced something of an aha moment. “I realized this is what I want to do,” Gleason said.
The burned woody debris on the snow is one of the critical variables in this research. Those burned bits make the snow darker, which then heats up more quickly when the sun hits the surface. It’s like wearing a black shirt on a sunny day. What’s more, burned forests don’t have the same tree canopy cover as a healthy forest, meaning more light reaches the ground. More sun on a darker surface melts the snow faster.