Our hardy volunteers join us to gather data on snowpack that will help predict future streamflows.
Many thanks to Kim Briggeman and Tom Bauer from the Missoulian for joining us at our ‘How to Track Snowpack’ event this past Monday, and for covering the day’s material in such an informative and comprehensive way. We’ve cross-posted the article below, or you can read it here.
And, if you missed this week’s event, we still have two ways for you to participate as a volunteer and assist with snowpack monitoring this winter. Join us on March 24 or April 21 for a field trip on skis or snowshoes up Ambrose Creek near Stevensville, and help collect real-time data that will be used by NRCS scientists to predict streamflows on the Bitterroot River. Find out more at clarkfork.org.
Expert offers lesson in measuring snowpack in Pattee Canyon
by Kim Briggeman of the Missoulian
Brian Domonkos made snow surveying look easy Monday. In truth it was.
A water supply specialist from the Natural Resources Conservation Service in Bozeman, Domonkos fashioned a couple of short lengths of hollow aluminum pipe into a snow tube, which he dropped vertically into the snow just off the Crazy Canyon trailhead in Pattee Canyon. It sliced through the old snow to bare ground, and came back up with 10 1/2 inches worth of snow.
It’s not always so simple, Domonkos said. “You get out to the Cascades and the Sierras, it’s amazing some of the techniques they have to sample snow and punch through the ice layers in some of the deeper snowpack,” he said. Sometimes it takes a tube 10 sections long to get to the bottom.
“The Snow Survey manual actually shows where you have one guy get on top of the shoulders of another guy to help drive it down,” he said with a chuckle. “That is an approved snow survey technique.”
Domonkos was invited to Missoula by the Clark Fork Coalition for a free presentation on how the experts track snowpack. Thirteen people showed up to watch. Snow depth isn’t ultimately what he’s looking for, Domonkos said. The snow tube has been used since snow surveying began in the Sierras in 1909 to monitor the levels of Lake Tahoe. It lets its operator measure the density of the snow and translate that into a snow water equivalent – in essence the depth of water that would result if you melted the entire snowpack at once. In Pattee Canyon’s case, that depth at noon on Monday would have been 2 inches.
Whether that’s an indicator of what will make it into Pattee Creek during the spring is another matter, Domonkos said. There are 90 designated “snow courses” across Montana, many of them visited during five working days of each winter month. The good ones have been proven over the years to correlate their SWE readings with streamflow levels down below. For his demonstration, Domonkos chose an open area on a slight downslope and away from a canopy of trees that would make snow depths inconsistent.
“We’re kind of at the headwaters of Pattee Canyon, so actually this is probably not a bad site as long as it represents the area we’re in,” he said. “But who knows if this place right here is going to truly represent the general snowpack that’s then going to become the streamflow? There’s only one way to find out and that’s to sample it for a few years and see if it correlates to streamflow.”
Snow courses typically are set up at off-the-path places in the woods, usually with 10 survey points along a transect. Until computers came into the picture, snow tubes and snow courses were the sole sources of snowpack data. Now there are another 90 Snotels in the state – sophisticated snow telemetry sites that electronically measure snow depth, snow water equivalencies, temperature and other data, then bounce microwave signals off the ionsphere “shield” and back to a master station on Earth.
While important collectors of real-time data, Snotels rely on proper placement at snow sites. And for that, the old-time snow courses remain invaluable. “If you don’t sample the snow when you put a Snotel site in you’re going to have to take that $25,000 to $30,000 installation out and move it, sometimes (as little as) 100 yards,” said Domonkos.
Some Snotels and snow courses offer more bang for the buck than others. One of the good Snotel sites is set up just off a ski run at Lost Trail Pass, where it can forecast streamflows for Idaho’s Salmon River as well as the Bitterroot and lower Big Hole drainages. “We get kind of a triple play out of a site like that,” Domonkos said.
The latest readings indicate snowpack at 89 percent of normal statewide and slightly lower than that west of the mountains. That may be inflated somewhat compared to past readings, Domonkos said. The 30-year norms this year exclude the decade of the 1970s, a relatively moist 10 years, and include 2001 to 2010 – “very dry years,” according to Domonkos.
Snowpack readings used to be the purveyance solely of streamflow forecasters, but that has changed. “Now the data is used for everything,” said Domonkos. When the Snotel site went down in Hoodoo Basin in Mineral County a little over a month ago, “we had snowmobilers emailing us every single day asking why is the site down? What’s going on? Recreationalists use it a lot any more,” he said.
His office also gets regular inquiries from those studying climate change. “It’s amazing some of the inquiries we get internationally about how our data is generated and how we collect it,” said Domonkos.