Winter is drawing to a close, and with it, so are the chances of boosting snowpack across the Colorado River Basin.
The mountains in Colorado, Utah, New Mexico and Wyoming saw a cluster of storms last month that aided their snowpack levels. But it wasn’t enough to make any meaningful dent into the forecasts, said Brenda Alcorn, a forecaster at the Colorado Basin River Forecast Center.
We “saw a really nice bump” from storms in February, Alcorn said during a briefing Friday, “but as we dried out and warmed up in the later part of the month, that came right back down. So, the forecast for the Lake Powell inflows did not change.”
As of March 6, snowpack above Lake Powell was at 88% of average; “average,” in forecasting, refers to the average precipitation in the area between 1991 and 2020. That’s similar to the snowpack level last month, which was 86% of normal as of Feb. 1.
Drier soil conditions in Utah and other parts of the basin have reduced runoff efficiency, meaning more of the water running off the mountains this spring will be absorbed into the soil instead of making it to the Colorado River and its reservoirs.
Forecasters currently predict that runoff into Lake Powell between April and July of this year will be 67% of average, which they also said at the start of February.
That’s down from what they predicted in January, which was a runoff of 81% of average, and a fall from December’s prediction of 92% of average.
The basin’s snowpack typically peaks in early April before melting into the Colorado River and its tributaries over the spring and summer, eventually flowing into Lake Powell and Lake Mead. The river system supports 40 million people in the western U.S.
“When we get to March 1, we’re about 80% through the normal snow accumulation season, so kind of running out of time to make up any deficits,” Alcorn said.
Right now, Lake Powell is 33% full. Last year, it peaked at 42% full in July.
The seven states that depend on Colorado River water — Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming — are in the midst of negotiations about how the river and its reservoirs should be operated after 2026, when current guidelines expire.
The Colorado River has struggled under drought conditions in recent years. Tension in the negotiations stems from the question of which states should have to reduce their use of the river’s water, and by how much.
