(CN) — A study published Monday in the Proceedings of the National Academy of Sciences found shocking effects from wildfires as the season turns, proving that rampant summer burns go beyond havoc on habitats.
Researchers examined wildfire zones and snowpack — an essential water source. Snowpack not only keeps rivers and streams flowing but replenishes reservoirs every year. In fact, a third of the water used in California comes from melted snowpacks. Unfortunately, there is a significant overlap in wildfire zones and essential snowpack regions, which sounds climate change alarm bells.
Stephanie Kampf, the study author, and her co-authors found that late-melt snow zones have experienced a 70% increase in area burned by wildfires. Additionally, in the late-melt area of the Southern Rockies, the area burned in 2020 was more than the previous 36 years combined. Steven Fassnacht, one of the co-authors and going on 30 years of studying snowpack, says that the overlap between snow and fire wasn't a huge concern until 2020.
"In this particular study, we look at the timing of snowpack disappearance and how that's accelerated, and it's 18 to 24 days earlier, which if we use that as a metric, means the water is going to come out of the system two, three, almost four weeks earlier than it normally does which has a profound impact on water resources management," Fassnacht said in an interview.
Previously, wildfire burns stayed in lower elevation forests where there was no persistent snowpack. With high elevation burns, the forest canopy disappears and no longer shades the snowpack. Without that level of leafy protection, the sun melts the snow faster. Additionally, the ash and other dark debris left behind from the wildfire makes the snow absorb more heat instead of reflecting the sunlight.
Protecting the essential snowpack isn't as easy as simply putting out a fire. Fassnacht said even house fires can't always simply be extinguished and that at a certain point it becomes damage control- the same goes for wildfires. However, the study can inform impacts on water resources and give insight into coping with a changing climate.
In recounting seeing plumes from a 2020 wildfire in Colorado, Fassnacht experienced just how close the overlap between fire and snowpack has gotten.
"It was not close to 100 degrees on the Sunday of Labor Day and the wildfire was burning — and then it snowed two days later. That's an indication of just how much the climate is changing that variability. All that did was slow things down. The fire was able to continue burning underneath the snowpack," Fassnacht said.
With less snowpack up at the top, less runs down and hinders wildlife recovery. Animals relying on water that is now sparse and the ground being left dry after the regular seasons of replenishment can have forest health effects for generations. The researchers noted that areas with more sun and low-altitude regions are more prone to the lasting snowpack effects from wildfire burns. For example, trees in the Southern Rockies rely on snowmelt and stop growing once the snow is gone.
"The ecosystem does rely on this high flow that comes out of snowmelt, and having water come out of the system earlier will change the nature of it and it has the potential to stress the system," Fassnacht said.
While wildfires continue to devastate habitats and now deplete key water sources, Fassnacht is hopeful and inspired by science students and budding researchers that are helping to build the future and ask difficult questions.
"As long as we can agree upon that we need to act, we need to respond for our future, our kid's future, etcetera, then I think that provides some hope," Fassnacht said.
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