The amount of snowmelt expected to reach the key reservoirs on the Colorado River this spring is far below the median of the last two decades, despite near-normal snowpack levels and heavy March storms across the basin.
Snowpack across the entire Upper Colorado River Basin sits at 95% of median as the winter draws to a close, according to a report released this week by the Colorado Basin River Forecast Center. But only about 4.5 million acre-feet of water are expected to flow into Lake Powell as snow melts across the Upper Basin — 70% of the median amount recorded between 1991 and 2020.
That means there is little hope that spring runoff into the crucial river that makes modern life possible across the Southwest will significantly raise water levels in the region’s two major reservoirs: Lake Powell and Lake Mead.
Both reservoirs — which store water for users in Arizona, California and Nevada — are about a third full and rely on snowmelt from the river basin upstream to be replenished. The amount of snow in the Upper Colorado River Basin generally peaks in early April.
“It’s hard to recover storage with a below-median year, which is where we are,” said Bart Miller, the healthy rivers director at Western Resource Advocates. “The seasonal forecast for the whole basin suggests we’re in for another dry year.”
The below-median inflow forecast comes as representatives from the seven states that rely on the Colorado River continue critical negotiations on how the river should be apportioned in the coming decades. The negotiators are working out how to divide cuts to water supplies as the river’s flows shrink and precipitation becomes less reliable.
Below-normal runoff is becoming a norm that must be dealt with, Miller said. Research shows that warmer temperatures, drier soils that suck up water and more variable precipitation — all fueled by climate change — have significantly reduced runoff in the Colorado River Basin. Those are among factors that contribute to the discrepancy between normal snowpack and below-normal inflow to Lake Powell, Miller said.
“As a basin, we’re having to face the fact that there is more demand for water than the river can provide,” he said.
Water levels in Lake Powell have generally declined since 2000.
“If the trend continues over a few years, we’ll see ourselves again talking about Lake Powell reaching ‘dead pool,’ ” Miller said, referring to a scenario where the reservoir’s water level drops so low it can no longer be released downstream.
Divide from north to south in Colorado
The amount of snow in Colorado and across the Colorado River’s upper basin varies greatly by region. Generally, more snow is on the ground farther north, and it becomes more sparse south of Interstate 70.
Northern areas of Colorado — including on the Yampa River and near the Colorado River’s headwaters north of Kremmling — have above-normal snowpack.
But conditions worsen farther south. The Dolores and San Juan river basins sit at 74% and 65% of median, respectively.
Drought is expected to expand across much of Colorado this spring, according to a drought outlook prepared by the National Weather Service.
Drought already stretched farther across western Colorado in February and March, and a quarter of the state was in drought conditions as of March 11, according to the U.S. Drought Monitor. Two pockets of extreme drought persist on opposite ends of the state: one in Larimer and Weld counties on the Wyoming border, and one in Conejos County.
This winter in southern and western Colorado has been one of the warmest on record, according to the Colorado Climate Center. Alamosa experienced its warmest February on record this year.
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