Study: Snowpack melts faster in burned forests
The snowpack is melting at much higher rates in places touched by wildfires from previous years.
This problem was observed by Dr. Anne Nolin, director of the graduate program of Hydrologic Sciences at University of Nevada, Reno, where she’s been studying the impact of snowpack in burned forests since 2011.
“I’ve done some very preliminary reconnaissance work — getting set up to do some future research in the Caldor Fire area,” Nolin said.
She described the aftermath of the fire as like looking at a black-and-white photo.
“A healthy fire will burn the understory, burn the small trees – but this fire just burned everything.”
Nolin observed that the fire was so strong that it had even burned the soil, which in turn may cause debris and sediment to flow into waterways, disrupting the clarity of the water.
She explained that the snowmelt process is being sped up by something called the “Albedo Effect,” meaning the reflectivity of the snow.
According to Nolin, after the trees have been burned, the black carbon absorbs double or triple the amount of solar radiation than before the tree was burned.
“If you double the amount of energy that’s absorbed by that snowpack, it heats it up fast and it will melt it a lot faster. If you have even more light absorbing particles, you’re going to triple or even quadruple the amount of energy that’s being absorbed by that snowpack of the sun’s energy.” Nolin said.
Once the snow melts and uncovers the dark debris below, the entire landscape begins to absorb the energy, which in turn creates a much dryer environment.
“So you end up having this kind of vicious cycle of snow melting earlier, more energy being absorbed, the surface of the land warming up more … that patch of snow will melt off weeks earlier than it would otherwise,” Nolin said.
Kelly Gleason, one of Nolin’s former students, performed a study where she found that black carbon can cause these adverse effects on the snowpack for up to 15 years.
Nolin has observed that there has been a large overlap between forest fires and snow zones.
The quality of snow is expected to change in areas affected by fire, which will have a negative impact on ski resorts that were touched by the Caldor Fire — such as Sierra at Tahoe.
As far as avalanche safety, Nolin believes that there may be a possibility for further instability.
“I can imagine that if you burn off a forest on steep slope that otherwise is snow covered, that you might potentially increase the probability of an avalanche because you have less anchoring material,” Nolin said.
Nolin also stated that over the years she has observed dryer Novembers, warmer winters with more rain on snow events, and earlier snow disappearance dates.
“I think we’re really in a bind where we have to try to figure out how to create healthy forests and reduce climate change, because there’s too much carbon pollution in the atmosphere… and what people can do is push for change, demand change.”
Elizabeth White is a staff writer with the Sierra Sun, a sister publication of the Tribune. She can be reached at email@example.com
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