Dry Soils, Western Slope Drought Cut Into Any Help CO Snowpack Can Offer Downstream States
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Colorado has also been missing out on its late summer monsoon rains the last few years. Assistant state climatologist Becky Bolinger said that means the soils don’t have a chance to catch up on moisture until the snow melts. “Your soils are dry, which gets into this unfortunate feedback loop of hot soils, evaporating dry and hot air,” she said. Bolinger said those dry soils from the fall soak up the snowmelt that should flow into streams in the spring. Last year was a good example — no big monsoon showed up in 2020, and “incredibly hot temperatures” dried out the soil.
In years that start with a water deficit, like this one, melting snowpack saturates the soil first. “In order to have a normal runoff season and get what you need into the reservoirs, you need above-average snowpack,” Bolinger said. Bolinger said the Colorado Climate Center is working on a project that looks more closely at how much soil moisture plays a role in the snowmelt season.
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Some parts of Colorado rely on snowpack as its central water source. Sonja Chavez manages the Upper Gunnison River Water Conservancy District, where snowpack levels are around half of normal. With less snow melting off quicker, Chavez said it’s shortening the recreational season. If the snowpack was above-average, she said there could be six months of a season on the rivers. “When you're in drought like we are right now, that season is concentrated into maybe four months,” she said. Low river flows can mean bad water quality from higher concentrations of metals and other contaminants, she said. The lack of snow and monsoon rains also has a big impact on ranchers in the area, who are reporting lower hay production and smaller herd sizes. “So this year we're starting to see our producers reduce their number of their cattle herd, and that has trickling economic effects throughout our basin,” she said.
Chavez said there’s a lot of worry about wildfires since the Gunnison River Basin is surrounded by federal lands. Kelly Gleason is an assistant professor of ecohydrology at Portland State University. She’s researched how the effects of climate change on snowpack influence wildfire activity. Gleason said that snowpack has declined dramatically across the West and other mountain states. When that snow melts earlier, it’s like opening a dam in the spring, she said. The result is less water available in the summer months for both people and ecosystems. Another symptom of snow disappearing from the landscape earlier is an extended drought and fire season, Gleason said.
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https://www.cpr.org/2021/05/17/dry-soils-and-drought-mean-even-normal-snowpack-cant-keep-up-with-climate-change-in-the-west/