Record warm temperatures across Nebraska, Colorado and Wyoming have led to significant drought conditions and low snowpacks.
That could be a problem for Nebraska because much of the water that flows into its rivers begins as snow in the mountains to the west. As the snow melts through spring and early summer, it feeds streams, reservoirs and irrigation systems across Nebraska.
Lindsay Johnson, a climatologist at the National Drought Mitigation Center, said snowpacks act as a stored water supply.
“Snow is hard just because it sometimes will look like it snowed, and everything should be better,” Johnson said. “But that moisture is locked away for now until it becomes liquid again.
A snowpack is measured using snow water equivalent, or SWE, which estimates how much water is stored in the snow. The data is collected by a system of automated climate sensors called SNOTEL that measure SWE, accumulated precipitation and air temperature.
This winter, many of these stations are reporting below-normal levels. As of Feb. 10, the U.S. Drought Monitor showed that 52.9% of Wyoming, 57.7% of Colorado and 59.4% of Nebraska is in a drought.
Darren Snively, a meteorologist at the Cheyenne, Wyoming, National Weather Service station, said warmer temperatures have played a major role in this.
“We’ve had a pretty persistent large upper ridge anchored over the western half of the country, bringing near-record warmth and really the lack of precipitation, and that has to do with the lack of snow this season,” Snively said.
Some stations in Wyoming, like the Laramie Range, have recorded low readings.
“We have a site that is reading only 4% of the median,” Snively said. “That’s very low for the current snowpack in that portion of the range.”
Rivers like the Platte River rely on mountain snowmelt, with 60% to 80% of its annual streamflow coming from snowpack in Colorado and Wyoming. Johnson said the biggest concern is not the initial spring melt, but what will happen later in the season.
“When things start melting, we'll get that first spring snowmelt, which we’re like, ‘yay’, but it won't continue because it’ll run out,” Johnson said. “That’s when it becomes concerning about this very low number right now.”
Lower amounts of runoff may force farmers and communities to rely heavily on groundwater, reservoirs and aquifers. These take longer to recharge and are already under strain in some areas.
Still, experts say it may be too early to know how the season will turn out.
“March and April are climatologically the snowier months of the season for the eastern Rockies, so we still have some time to make up in that regard,” Snively said.
Drought experts are continuing to monitor conditions in the mountains and update their maps weekly.
Current drought maps are available online.