Earth Protect Blog

AVERAGE SNOWPACK

By Elise Schmelzer

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It was an average year for Colorado’s snowpack — and that’s great news.

The statewide snowpack sat at 109% of the 30-year median on Wednesday, just a few days shy of the normal peak of snowpack for the state. Every major river basin in the state also recorded above-median snowpack, reducing the risk of large, uncontrollable wildfires and boosting the state’s water supplies.

Despite a slow start to the snow season, large storms in February and March boosted the amount of water that will become available as mountain snow melts. The statewide snowpack had lagged behind the median until early March.

“We’re in a good position,” said Becky Bolinger, the assistant state climatologist at the Colorado Climate Center. “The key is that just because we’re reaching peak snowpack does not mean that it should stop snowing.”

But not all of the Western U.S. is faring as well. Snowpack levels in northern states along the Canadian border remain dismally low, prompting warnings of coming drought and water shortages this summer.

In Colorado, the major river basins in the state ranged between 104% and 112% of the 30-year median this week. At 119% above the median, the Arkansas River basin had the best year.

Continued snow in the mountains and slowly warming temperatures through early May will be key to extending the snowmelt, Bolinger said. If temperatures warm too quickly, more moisture will be lost to the atmosphere through sublimation — a process in which snow transitions from a solid to a gas without melting because of warm, dry air.

The average snowpack this year also will minimize the risk of large, uncontrollable wildfires because vegetation will dry out later, Bolinger said.

“When we have a normal snowpack, you can generally think that they’ll be more typically behaving wildfires and a little more controllable,” she said.

This year’s snowpack is better than levels recorded in 2022 and 2021, but far less than the banner year recorded in 2023.

The 2023 snowpack helped boost the amount of water stored in the state’s reservoirs. Collectively, the reservoirs now sit at 60% of capacity, up from 50% at the same time last year, according to data from the U.S. Department of Agriculture.

Snowpack in the Upper Colorado River Basin is at 114% of the median depth, which is critical for restoring water levels in Lake Mead and Lake Powell, the two major reservoirs in the Southwest. But even if snowpack is above average, the amount of water that reaches the reservoirs can be below average because of dry soil or high heat, said Dan McEvoy with the Western Regional Climate Center.

“You need way more than average — you need a really big year, like last year” to reach average flows, he said.

Snowpack in many of the southern Rocky Mountain states — namely New Mexico, Arizona, Colorado, Utah and Nevada — is plentiful, according to the National Integrated Drought Information System.

Not all of the West is enjoying such good water news, however.

Snow levels are far lower in Montana, Idaho, Washington and northern Wyoming. Many river basins in those states sat at less than 70% of the median as of Sunday, the most current data show.

“It’s just been extremely dry,” McEvoy said. “The snowpack in some of the locations there are the driest on record, and those records go back 40 or 50 years.”

That lack of snow likely will lead to moderate or extreme drought across the northern Rockies in the spring and summer.

“At this point in the season, we don’t anticipate a recovery in many locations,” Kyle Bocinsky, director of climate extension at the Montana Climate Office, said in a news release warning of drought and water shortages. “The public should know that it really is not looking good for our water supply going into the spring and summer.”

The smaller snowpack will yield lower river flows for recreation and agriculture. It will also heighten the risk of hotter, more dangerous wildfires, McEvoy said.

The rate at which the snowpack melts across the West will be an important factor in how dry the summer becomes, McEvoy said. As spring heat waves become more common and more extreme because of climate change, snowpack depth measurements can shift dramatically in a matter of weeks, he said.

If the snow melts too quickly, the water will dissipate sooner — and vegetation and soils will dry out sooner than expected.

“Keeping an eye on how fast the snow comes off the mountains is almost as important as watching the snow accumulating,” McEvoy said.