Snowpack/runoff/precipitation news: Statewide snowpack stands at 148% of average

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From the Fort Collins Coloradoan (Bobby Magill):

[Don Day of DayWeather in Cheyenne] said a major slow-moving storm system is in position to soak Northern Colorado between Monday and Thursday, but there is a possibility the storm could track to the north of the state. Another could blow through the following week, he said. The storms bring the possibility of heavy rain to the mountains, kicking off the runoff season, which could see significant flooding on the Poudre River. “The next four days, we’re going to get the day and nighttime melting,” Day said. “Next week, we’re going to get rain on top of that. It’s the start of about six to eight weeks where we’re really going to be on pins and needles watching (for flooding).”[…]

The water content of the snowpack west of Fort Collins is extraordinary. At Joe Wright Reservoir along Colorado Highway 14, the snowpack’s water content was 194 percent of normal on Wednesday. The South Platte River Basin average is 153 percent, with some snowpack monitoring sites in the North Platte Basin reading greater than 200 percent. Rocky Mountain National Park spokeswoman Kyle Patterson said heavy spring storms above tree line have piled up to 14 feet of snow along parts of Trail Ridge Road that had very little snow this time last year.

With respect to snowpack the rich get richer and the San Luis Valley is still dry as can be. Here’s a report from Ruth Heide writing for the Valley Courier. From the article:

Precipitation in March, for example, was “generally below average across the area,” the Weather Service stated. Alamosa received only 0.02 inches of precipitation in March. “This is 0.44 inches below average for the month and makes March of 2011 the second driest March on record in Alamosa,” according to the Weather Service. At the same time temperatures were mainly above average across the area. Alamosa temperatures during that time period came in 3.9 degrees above average making March the 11th warmest on record in Alamosa, according to the Weather Service…

As of Wednesday, the Natural Resources Conservation Services SNOTEL report for the Upper Rio Grande Basin showed snowpack at 100 percent of average including Wolf Creek Summit, which showed 105 percent of average and Lily Pond at 63 percent. The eastern side of the Valley, the Sangre de Cristo Mountain Range, sat at 54 percent of average on May 4. Overall reservoir storage this spring was running below average across Southern Colorado, with storage in the Rio Grande Basin on April 1 at 82 percent of average overall, below storage levels for that time last year, according to the Weather Service.

Stream flow was generally at or below average on April 1 across the Rio Grande Basin, the Weather Service added. “Water users can expect below average to well below average flows this spring and summer. April to September runoff projections range from 34 percent of average for Sangre De Cristo Creek to 76 percent of average for the Rio Grande at Thirty Mile Bridge, Saguache Creek near Saguache and the inflow to Platoro Reservoir. “The lowest stream flow forecasts in the state are concentrated along the Sangre de Cristo Mountains affecting both the Rio Grande and Arkansas Basins. Runoff forecasts along some of these smaller tributary streams range from 40 to 60 percent of average. Water users across Southern Colorado should plan for late summer shortages especially if the monsoon is disappointing this year.”

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Here are the notes from this week’s “NIDIS Weekly Climate, Water and Drought Assessment Summary of the Upper Colorado River Basin” hosted by the Colorado Climate Center. Click on the thumbnail graphic to the right to see the precipitation for April.

From the Summit Daily News (Janice Kurbjin):

A graph by the Blue River Watershed Group shows that the 2011 snowpack in the Colorado River Basin reached about 165 percent of average at the end of last month, surpassing 1984’s snowpack which hit about 160 percent of average in May. Natural Resources Conservation Service data has the Colorado River Basin at 151 percent of average. Water content at Copper Mountain, which flows into Ten Mile Creek, is at its highest this year, and the snow survey site on the Snake River above Keystone is at 231 percent of average…

“The last two weeks in April were when we really got pounded with some of the biggest storms of the season — pretty relentless — at some of these locations,” said snow survey supervisor Mike Gillespie of the Natural Resources Conservation Service…

The North Platte, Yampa and White river basins have all hit 165 percent of average snowpack, and the South Platte is at 150 percent of average. The Arkansas River is at 112 percent of average.

The high snowpack is causing water officials, like Steger, to take precautions in water management. Steger has a balancing act on his hands — not drawing Dillon Reservoir down so much so it can’t fill, but trying to mitigate overfill and downstream flooding. He estimates there’s a 90 percent chance the May through July total inflows would exceed 210,000 acre-feet, and a 10 percent chance inflows could reach 290,000 or more. The 30-year average is about 160,000 acre-feet…

Statewide, snowpack is at 135 percent of average, and at 175 percent of last year. That reflects a less bright situation in southern Colorado, where “it’s a totally different story,” Gillespie said. The Rio Grande and southern Arkansas rivers below Canon City are seeing below average runoff and are already well into the melt season. That trend extends into southwestern Colorado — the San Miguel, Dolores, Animas and San Juan rivers, Gillespie said.

From The Denver Post (Joey Bunch):

“The longer the melt is delayed, the more likely we are to see stream flows that we haven’t seen in a decade or more, possibly back to 1984,” said Michael Lewis, associate director of hydrologic data at the U.S. Geological Survey’s Colorado Water Science Center in Lakewood…

At a news conference Wednesday morning, the Natural Resources Conservation Service, which measures snowpack, said accumulations north of the Gunnison River basin range from 148 percent to 170 percent of their 20-year averages, setting records for depth and water content.

From the Estes Park Trail (Juley Harvey):

The runoff is coming, as sure as there is snowpack and warm weather. It`s a matter of when and how much. Town and county officials held a public meeting Monday night, warning residents to expect a 30-percent higher runoff than last year. Don`t panic, but do prepare is the message. Also, officials said the responsibility to protect private property is that of the residents. While sandbags will be provided in declared emergencies, it is up to the residents to monitor their situations and take proper precautions, such as having flood insurance and watching the weather carefully.
“We`ll pray for gentle warming!” one resident concluded, as the meeting ended…

The Natural Resources Conservation Service of the United States Department of Agriculture is watching, and supplied these snow survey results for April on its website, as of April 27. Deer Ridge at 9,000 feet reported an average snow depth of 33 inches, 400 percent of last year’s; Hidden Valley at 9,480 feet reported an average snow depth of 56 inches and 226 percent of last year’s; Willow Park at 10,700 feet reported 95 inches of average snow depth, 219 percent of last year’s; and Bear Lake at 9,500 feet averaged 81 inches of snow, 208 percent of last year’s.

Andrew Gilmore of the Bureau of Reclamation, Eastern Colorado Area office, said they look at Bear Lake and Lake Irene sites to measure the snow pack and predict what might happen to the reservoirs. “We’re setting new records (at the two locations),” he said…

Gilmore said operators like to maintain the water flowing below the dam [ed. in the Big Thompson] as well as at Lake Estes at 1,100 cubic feet per second (CFS).

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