Snowpack/runoff news: Snowpack on Grand Mesa low for April 1, Sangres melting out

Click on a thumbnail graphic to view a gallery of snowpack data from the Natural Resources Conservation Service:

From the Grand Junction Free Press (Stephanie Kampf):

Throughout the West, communities and farms rely on melting snow for water supply. Each year, water managers track mountain snowpack levels in the spring to forecast the water supply for the summer growing season. For decades, snowpack conditions measured on or around April 1 have been used to generate river flow forecasts that inform water supply plans.

As of late March, the Snow Telemetry (SNOTEL) stations operated by the Natural Resource Conservation Service are showing very low snow conditions in many parts of the west. In drought-stricken California, the snow water equivalent (SWE), or water contained within the snowpack, is only five to 25 percent of the median for this time of year, with many stations having no remaining snow. Oregon snowpack is not much higher, at only sevent to 38 percent of the median. California hasn’t had an above normal snow year since 2011, leaving much of the state in the most severe category of drought.

Compared to California, snow conditions in the Upper Colorado River Basin look much better, but this is still a lower than normal snow year. SNOTEL stations above Lake Powell collectively are reporting SWE levels that are 74 percent of the median for this time of year. But up on the Grand Mesa, which supplies much of the drinking water for the Grand Valley, a hot, dry winter has left a near record low snowpack. Since records began at Mesa Lakes in 1987, the only year with a lower end of March SWE was 2002. At the opposite extreme, 2015 winter temperatures were among the highest recorded at both Mesa Lakes and Park Reservoir SNOTEL sites, with 15 days in 2015 reporting the highest recorded daily mean temperatures.

What does this all mean for flow in streams draining the Mesa? A short spring window still remains for snowpack to recover. At Mesa Lakes and Park Reservoir SNOTEL stations, the snowpack typically reaches its maximum level in late April, so spring storms could still boost the snowpack, provided temperatures stay cold enough for the snow to stay on the ground. But even if the snowpack recovers in April, the historical record suggests spring runoff from the Mesa will still be well below normal this year. In 2002, the record low snow year, the snowpack was not much lower than it is in 2015, and total runoff recorded downstream at the Plateau Creek stream gauging station near Cameo was only 15 percent of the median during April through July.

While water supply storage reservoirs help buffer from the effects of low snow years, several low snow years in a row can severely stress water supplies, as this year is showing in California. So, as the growing season begins, this is a good year to plan ahead for conserving water in the warmer months to come.

From The Pueblo Chieftain (Matt Hildner):

Medano Creek has begun to run early at Great Sand Dunes National Park and Preserve this year.

What normally is a small trickle coming down from the Sangre de Cristo Mountains at the beginning of April is now a broad stream welcoming visitors at the main parking lot and picnic area.

“In the 20 years I’ve been here, this is the earliest I’ve seen the creek come down,” Park Ranger Patrick Myers said.

Warm temperatures have prompted the arrival of what’s usually a May and June highlight of a trip to the park when the creek and the dune combine to form Colorado’s closest thing to beach front property.

Park Geologist Andrew Valdez, who also tracks weather at the dunes, said in an email that March’s average temperature of 39 degrees was five degrees warmer than average.

Peak flow measured where the stream leaves the forest is usually in late May at 40 cubic feet per second.

Tuesday’s flows were just above 12 cfs.

Those warm temperatures have taken a toll on the Sangre de Cristo’s snowpack, especially at the headwaters of Medano Creek above the park.

The snow there shrunk from 14 inches deep on March 24 to just one inch by Wednesday, according to a Natural Resources Conservation Service snow gauge.

The warm temperatures also have contributed to the thawing of the sand in the dunes, which when coupled with spring winds out of the Southwest, restarts the process that pushes the dunes against the mountains to the east.

Medano Creek, along with its counterpart Sand Creek on the park’s northern edge, help redistribute the sand in the opposite direction of the wind.

While the creek is normally a big draw when the park has its biggest crowds in summer, seeing it now can mean beating the crowds.

Over the last five years, park visitation in April has ranged from 9,000 to just under 11,000 people, roughly a fifth the size of the crowds that come in June and July.

Leave a Reply