This winter in the southern Rocky Mountains is shaping up to be one for the record books. And not in a good way.
Parts of the West are currently experiencing one of the driest and warmest winters on record. Snowpack is far below normal levels in southern Colorado, New Mexico, Arizona, Utah and California, leaving some to worry about this year鈥檚 water supply.
To get a sense of this year鈥檚 snowpack, head to a place like Berthoud Pass, an hour drive into the mountains west of Denver. The pass, which straddles the basins for both the Colorado and the South Platte rivers, is home to a SNOTEL site. SNOTEL -- a portmanteau of "snow" and "telemetry" -- is the system of hundreds of snow measurement sites throughout the Western U.S. that estimate the amount of water held in mountain snowpack.
The site is a short snowshoe hike up a hill off the highway, in a small clearing in the trees. The Berthoud Pass site was set up in the first generation of SNOTEL sites dating back to the late 1970s.
鈥淭his is at the higher range of where we do measure snow,鈥� says Karl Wetlaufer, the assistant snow survey supervisor for the Natural Resources Conservation Service in Denver. 鈥淲e鈥檙e well over 11,000 feet here.鈥�
Each SNOTEL site is a Rube Goldberg setup of meters and tubes designed to measure the weight of the snow. When snow falls it compresses pillows on the ground, filled with a sweet-smelling liquid anti-freeze. The liquid is displaced by the snow鈥檚 weight, and from the weight scientists can figure out the most important aspect of mountain snowpack: how much water is in it. The process is mostly automated, but the sites still require maintenance.
鈥淭here鈥檚 kind of some elegance in the simplicity. We鈥檙e literally just weighing the snowpack, second hand,鈥� Wetlaufer says. 鈥淎nd that鈥檚 the most accurate way to get the water content.鈥�
It鈥檚 meant to give a glimpse at how the winter is shaping up so cities, farmers and water managers all throughout the West can plan. So far, this year鈥檚 prognosis is bad.
鈥淛ust driving up through the mountains as we gain elevation there鈥檚 definitely noticeably less snowpack than we would expect as we approach the site,鈥� Wetlaufer says. 鈥淎nd intuitively you can just feel that we have a lower snowpack.鈥�
That鈥檚 even worse news considering Berthoud Pass -- currently at -- is one of the better sites for snowpack in the entire Colorado River watershed, which supplies water for about 40 million people in seven states.
鈥淭he hole we鈥檙e in now in terms of the snow deficit is going to be really hard to pull out of,鈥� says Jeff Lukas, who studies long-term climate shifts at the , based at the University of Colorado-Boulder.
If you add up the numbers at all the SNOTEL sites in the upper Colorado River, snowpack is at . It鈥檚 well below normal, halfway through the snow accumulation season. Essentially, time is running out to make up that deficit, Lukas say.
If the weather stays dry and warm through the spring, Lukas says it鈥檒l set the stage for the rest of the year.
鈥淵ou have vegetation growing and drying out and curing earlier,鈥� he says. 鈥淵ou鈥檙e setting yourself up for a worse than average wildfire season.鈥�
Forecasts for river flows by the Colorado Basin River Forecast Center are already taking the current diminished snowpack into account. Most streams this spring, some just slightly, with others extremely below average. Inflow to Lake Powell, the first major reservoir the Colorado River empties into on the Utah-Arizona border, is projected to be 54 percent of average this spring and early summer.
The good news for upstream water managers is that most smaller reservoirs in Colorado, Utah and Wyoming are storing above average amounts of water, boosted by drought-busting wet weather in the winter of 2016-2017.
鈥淲e can weather one bad year,鈥� Lukas says. 鈥淏ut in other parts of the West or even downstream in the Colorado River Basin, Lakes Powell and Mead are both sitting well below capacity.鈥�
We鈥檝e experience dry early winter seasons before, Lukas says. He lists 1981, 1990, 2000 and 2012 as analogous to this one -- dry and warm. In some of those years, the snow recovered later in the spring.
鈥淏ut overall that鈥檚 very bad company for us to be keeping,鈥� he says. 鈥淭hose years turned out to be -- all of them were quite a bit drier than average. And three of the four were in the bottom six or seven years of the last 50.鈥�
All that bad snowpack news means downstream states like Arizona, Nevada and California are anxiously looking toward the Rocky Mountains. The Colorado River -- fed by snowmelt -- provides roughly 40 percent of the Arizona鈥檚 water.
鈥淲e closely watch this. We know how important it is,鈥� says Tom Buschatzke, director of the Arizona Department of Water Resources. 鈥淚t鈥檚 a huge piece of Arizona鈥檚 water budget, and a life blood for the state.鈥�
Of all the states that rely on the Colorado River鈥檚 water, Arizona is in arguably the worst position to handle a dry year. Its reservoirs are currently sitting below average, yet to recover from a long-term drought that鈥檚 plagued the southwest for more than a decade.
On a scale of zero to 10 -- where zero is not worried at all and 10 is panic mode -- Buschatzke says he鈥檚 moderately worried about the state鈥檚 ability to withstand a dry winter.
鈥淚 am probably at about a seven right now,鈥� he says.
Add in the projections for climate change that show a future where the river鈥檚 supply is sapped even further, and thinking about the river鈥檚 future can be anxiety-inducing.
鈥淢ost nights it does not keep me up. There鈥檚 an occasional night where it does,鈥� Buschatzke says.
Back at Berthoud Pass, snow surveyor Karl Wetlaufer writes down measurements, using an aluminum tube to take core samples from the snowpack, and then weighing it. This more old-school method of measurement is still in use by surveyors across the West.
Wetlaufer isn鈥檛 panicking yet. There鈥檚 still plenty of winter ahead of us. It wouldn鈥檛 be unprecedented for some big storms to change everything. But the window for those Hail Mary snow storms is closing, he says.
鈥淲ith every week that goes by the probability of reaching a normal snowpack is less and less really,鈥� he says.
That probability is lessened even further by the current . They鈥檙e showing a likely chance of higher temperatures and lower precipitation this spring in mountainous regions that need exactly the opposite.
This story is part of a project covering the Colorado River, produced by KUNC and supported through a Walton Family Foundation grant. KUNC is solely responsible for .
