LAS VEGAS (KLAS) — February snowfall might have fallen behind January’s brisk pace, but the Upper Colorado River Basin will go into March still well above average snowpack levels.
With all the headlines about snow in California and Utah, the area that matters most to the Las Vegas valley and Lake Mead is the region around the Colorado River’s headwaters — where the river is born among the peaks in and around Rocky Mountain National Park.
Overall, the Upper Basin is at 133% of normal snow water equivalent (SWE) in the snowpack that will provide water for 40 million people this year, according to an update today from the U.S. Bureau of Reclamation. And while 133% is still quite a bit above average, the number has been shrinking since mid-January, when “atmospheric river” moisture dropped off.
Storms in the southern Rockies have helped elevate the numbers. Snow in the San Juan range and parts of southern Colorado have built snowpack levels far above average.
See how the snowpack levels have changed over the past two months (blue box in the middle of each image below):
And now, new snow is in the forecast. More than half of the next 14 days are expected to bring “moderate to heavy” snowfall in the central Rockies.
In five weeks, we will be near the typical “deadline” for building snowpack levels. On April 6 — the day scientists see as the usual peak of snowpack levels — all the weather watching will turn to watching the snow melt.
As the water stored in mountain snowbanks begins its long journey through creeks, rivers and reservoirs, the science will turn to new observations of how climate change has affected “normal” Colorado River conditions. More water absorbed into soils, more evaporation in hot, dry conditions — and the rising temperatures in the Desert Southwest.
Scientists have said that “normal” river flows are about 20% below where they were before the megadrought that began at the turn of the century.
Decisions by water managers in raising or lowering reservoirs along the river’s path, and how to meet the terms of a 100-year old “Law of the River” will become the focus. And even if the snowpack levels bring above-average water this year, it’s only temporary relief. Politicians and conservationists agree on that point.
