Dry Soils And #Drought Mean Even Normal #Snowpack Can’t Keep Up With #ClimateChange In The West — #Colorado Public Radio

In March of 2018 Karl Wetlaufer, a hydrologist and assistant supervisor with the National Resources Conservation Service Colorado Snow Survey, gestures to indicate how high snowpack has been in past years at the McClure Pass site. Data collectors would have to climb the rungs up to the second, higher door to access the shelter. Photo credit: Heather Sackett/Aspen Journalism

From Colorado Public Radio (Michael Elizabeth Sakas):

Brian Domonkos straps on a pair of cross-country skis and glides through the trees along Mosquito Creek west of Fairplay.

It’s May, but there’s still snow in Colorado’s mountains near the headwaters of the South Platte River.

Domonkos, the Colorado Snow Survey supervisor, gets to work measuring how much snowpack is left from the winter to runoff into streams, rivers and reservoirs this summer. These mountains trap snow in a natural reservoir. As it melts, it becomes the primary source of water for Colorado and much of the West.

Climate change is disrupting this delicate system in multiple ways. The overall trend shows less snowpack accumulation due to warmer temperatures. What does collect melts sooner and faster, which means less snow on the ground and a greater chance for wildfires.

Karl Wetlaufer (NRCS), explaining the use of a Federal Snow Sampler, SnowEx, February 17, 2017.

To measure the snowpack, the total seasonal accumulation of snow on the ground, Domonkos skis to specific points on what’s called a snow course. He then jabs a tall metal pipe into the snow to collect a core sample…

The snowpack at the South Platte’s headwaters is over 110 percent of normal levels for this time of year, but that’s not the case for the rest of the state. In southwest Colorado, it’s less than 40 percent in areas that are already experiencing a historic drought…

Year after year, unusually dry soils from warmer than normal temperatures and a lack of moisture are absorbing a lot of the water that melts from the snowpack. This means a lot of water isn’t making it into rivers and streams, essentially limiting the efficiency of the melting snow.

Even a year with an above-normal snowpack might not push Colorado out of a shorter-term drought, Domonkos said…

Dry soils are taking water

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…

In years that start with a water deficit, like this one, melting snowpack saturates the soil first…

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…

The effects ripple downstream

Poor snowpack efficiency doesn’t just impact Colorado. Reservoirs Lake Powell and Lake Mead are projected to shrink to historic lows in the coming months, which could trigger the federal government’s first-ever official shortage declaration. That would mean mandatory water cutbacks in Arizona and Nevada.

The Colorado River, which starts in the Rocky Mountains of Colorado, feeds those reservoirs. The snowmelt supplies water to millions of people downstream. The forecast for Lake Powell is just 28 percent of average levels…

From recreation to ranching

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…

What it means for fire season

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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