Volume 8, Number 1 - March 27, 2008
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Snow Is Like Gold In ‘Them Thar’ Hills
We’ve had plenty of white stuff up high this winter but how much water can we squeeze out of it for this summer?
Snow can be fairly dry (as it was earlier this winter) and lack enough moisture to ultimately keep our streams, lakes and irrigation ditches filled through August. And if that snow melts all at once or disappears too early in the spring, the longer-lasting water supply needed to keep summer pastures, lawns and meadows a healthy green wash away to the sea. About 75 percent of Wyoming’s water supply comes from high mountain snowmelt, so being able to measure precipitation and how much water it holds is key to forecasting the summer’s water as a resource.
It is Lee Hackleman’s business to keep track of Wyoming SNOTEL snow surveys and snow water equivalents (SWE) as the Natural Resource Conservation Service’s water-supply specialist. SNOTEL – “Snowpack Telemetry” – is an automated network using high-tech methods to collect snowpack, precipitation and other climate data from 85 Wyoming sites (and more than 730 remote high-elevation sites total in 11 western states). NRCS installs, operates and maintains the system to produce water supply forecasts after a congressional mandate in the mid-1930s.
Hackleman’s educated forecast for this season: a cool spring with normal or above normal precipitation – good news for those depending on a slow sustained snowmelt. “This spring’s supposed to be normal or above normal in precipitation from here on out but not with the higher temperatures,” Hackleman said. “They go hand in hand. If you get cooler weather you get higher precipitation. If the snow hangs in there it will fill the reservoirs more, with more late-seasonw ater.” These forecasts hold up very well for several weeks out, he added, with reliance on experience and previous similar patterns to forecast formore than a month ahead – “it’s the best guess anybody’s got, I guess.” “We did pretty well last month for this (month’s forecast),” Hackleman added.
In fact, these recent storms have pushed up our local water supply (in the form of wet snow). As of March 24, the Sublette County region’s SWE weighs in at 87 percent of average, up 5 percent from last week after these storms, according to Hackleman.
“You must have had some good storms up there,” he commented. “If we continue to get storms like that from now on it will be better. If you get some good storms (the SWE) could even go up into the 90s.”
Exactly one year ago, the Upper Green River Basin was measuring in at a paltry 65 percent–down from 70 percent the previous week“ and dropping” due to the unusually high temperatures that drove snow out of the mountains early, Hackleman said.
Sublette ranchers and recreators alike dread the driedup streams and ditches experienced last summer after early spring weather melted a lower snowpack too quickly to be beneficial throughout the summer.
“This winter has stayed cooler than past years,” Hackleman said. “It hasn’t started melting out so early.” Hackleman refers to his weekly “Monday report” for current SWE information and noted as of March 24, Sublette’s – and Wyoming’s – overall situation is looking pretty bright. “Looking at this you are a lot better off this year than last year,” he confirmed. “But it’s still below average.” (The average is based on data from the 1971-2000 base period.)
Report #18 states,” Good we are holding our own and actually gained 2 percent (across the state). We need more large snowstorms. Seven basins gained, two stayed even and four lost ground. Last year at this time the state average was
a miserable 69 percent with a low of 54 percent and highof 76 percent of average. This year the state average is 99 percent with a low of 87 percent and a high of 111 percent of average. Compared to last year, local trends show plenty of wet snow in other nearby basins as stated in the NRCS’s March “Wyoming Basin Outlook Report.”
• Hoback River drainage has SWE 87 percent of average, 122 percent of last year.
• Newfork River Basin SWE is now about 80 percent of average (115 percent of last year).
• Greys River drainage is at 96 percent of average and 126 percent of the previous year.
• Big Sandy-Eden Valley Basin is at 78 percent or 114 percent of last year.
“Monday reports” can be found online at http://www.wrds.uwyo.edu/wrds/nrcs/nrcs.html or received weekly by email; call the NRCS Snow Surveys office in Casper at 307-233-6744 or 6743.
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