Melting snow flows into creeks and streams, and ultimately into drinking water for people living in the arid West. Since 1935, farmers and cities alike have relied on the U.S. Department of Agriculture's Cooperative Snow Survey Program to predict runoff and know how much water to expect. Snow surveyors from Natural Resources Conservation Service and the other cooperating agencies collect data from thousands of snow survey sites several times each winter.
In 1977, NRCS began developing a network of automated radio telemetry data sites for collecting snow survey data, but some information is still collected manually involving long treks into remote areas, often in bad weather.
We tagged along with some of these quiet heroes who, quite literally, go to great lengths to understand just how much water will come out of your tap.
© Frani Halperin/H2O Media, Ltd.
Jamie: It’s going to be a long day for Butch Horner and Mike Ardison. The sampling kits are loaded, the snow mobiles are on trailer and they’re headed up to the mountains above Boulder, Colorado to do the first of two snowpack surveys for the Natural Resources Conservation Service.
By the time the day is over, they’ll have traveled hundreds of miles— some by truck, some by snow mobile and the rest in snow shoes or skisall to get vital data about snow— how much there is, and more importantly how much moisture it contains. That water content will be a crucial piece of information for manyfrom farmers and cities, to whitewater rafters and fly-fishers. Snowpack data will help them predict just how much water to expect in rivers, lakes and streams.
Frani and I catch up with Butch and Mike as their rig pulls off west of the "Peak to Peak Highway."
Jamie: So we’re up here at Brainard Lake. Where do we go from here?
Butch Horner: We’ll just be going down the hill a little ways and it will be off to the right.
Jamie: We park our car a bit down the road and strap on our snowshoes. We follow Butch and Mike through a pine forest bending back tree limbs as we go. There’s no trail per se— but these two know exactly where they’re going.
Mike Ardison: Alright, so this is the course. So you see that little yellow sign at the far end? That’s the starting point. And then this one right here is our end point. So in between these two points we’ll take five samples. They’re all at pre-determined spots and we do those in the same spots from year to year.
Jamie: Butch unpacks the sampling equipmentthe three foot sections of tubing he’ll connect and drive deep into snow to gauge the it’s depth.
Butch: These sampling tests run about $5,000.
Jamie: The idea of correlating mountain snow to the amount of runoff when snow melts is credited to Dr. James E. Church, a professor at the University of Nevada. In 1906, Dr. Church developed the first snow sampling seta hollow 10-foot tube made out of steel. After a number of years of comparing Winter snow depths in the mountains above Lake Tahoe he was able to predict water levels in the lake the following Summer.
Mike: Well, we might as well head on down to the start of the course.
Jamie. We follow Mike and Butch, careful not to step in the sampling area. Butch begins the survey by plunging the tube deep into the snow. He calls out his readings to Mike who records them in his ledger.
Mike: 44… Frozen... What’s the core length?
Butch: Core length is 49½.
Butch: 48. (Referring to weight)
Jamie: After you get the snow sample you weigh it?
Mike: Yep. First we’ll tear our tubes so we know what our base tube weight is. Then we’ll go for depth. When you bring the tubes up after measuring the depth you’ll have what’s called the core length. And then we weigh it. And then from there we’ll subtract that from the tear, and then from that divide it by the depth will give us the density.
Jamie: This exchange will repeat four more times as we progress down this relatively short snow course. Most courses have between 10-14 sample points, but some can get into the hundreds. The two of them are completely in sync and seem to really enjoy their jobs.
Jamie: Frani asks Butch how long he’s been doing survey work.
Butch: I’ve done a lot of different things.
Frani: Is this your favorite job?
Butch: I like this job. Yeah. This is a great job.
Frani: This is very cool.
Mike: It’s kinda part scientist, part contractor, part lumberjack. There’s a multitude of things that play into it.
Butch: Yeah, cause you never know what you’re gonna run into when you get to a site. The bears, they chew up our snow pillows, so then you have to replace snow pillows—
Frani: Ok, What’s a snow pillow? That’s not where they hibernate?
Butch: That’s what we use to measure the weight of the snow out on our automated sites. And what happens there is that they look kinda like a water bed. They’re 10-foot across and round. And the snow lands on them. And when the snow lands on them, there’s a little tube going out of the bottom and going up into our shelter called a monometer. And so when the snow lands out here it pushes the fluid up inside the building. And then we measure the height of that fluid then we know how much the snow weighs.
And we also have a snow depth sensor that shoots a radio wave down hits whatever’s down there and bounces back up. So we know what it is in the summer when there’s no snow there so when snow starts building up we can know how deep the snow is at the site. So that’s how those automated sites work.
Jamie: As we come to the last measurement, Mike shows us his ledger that is now full with numbers reflecting today’s take— depth of snow, water content, density and one really important area for remarks. That’s the difference between the automated sites that Butch was describing and the manual sites. Manual snow surveys allow for human observation that will be particularly useful now in Colorado given the severe flooding last September.
Mike: Dirt plugs, if we know if they’re frozen or if they’re still saturated or if they’re dry, really helps us as far as forecasting because then we know when it does come time for melt-off if a lot of it is going to go directly into the ground or if it’s going to runoff over the ground.
Mage Hultstrand: So we take all that data and put it into a streamflow forecast.
Jamie: That's Mage Hultstrand, Assistant Snow Survey Supervisor for the NRCS. We met with her in her Denver Federal Center office and asked about how the snow survey data will be used.
Mage: Every month the forecasters, (they’re located in Portland, Oregon) take all the data that we provide and come up with an estimate of what they think total volume is going to be past a single point. Usually it’s a USGS gauge...and how much volume of water is going to flow past that point.
Jamie: So right now the information that you’re collecting is extremely critical.
Mage: Exactly. It’s going to be pretty important especially for all the tributaries along the South Platte that were really hit with floods this year. Because they’re not really sure how those rivers are going to react. It’s important because there’s a lot places where the river is now flowing it didn’t use to flow and a lot of homes that could be endangered if we do have flooding conditions. They have pretty large snowpack right now and it’s really going to depend on those temperatures how quickly that runs off.
Jamie: With so much at stake for the safety and future of towns in the South Platte Basin you would imagine there to be several NRCS teams gathering data. But you would be wrong. NRCS has a full-time staff of three the result of Federal budget cuts.
It’s a lot to ask of 3 people whose territory stretches from Arizona to New Mexico to Colorado and Southern Wyoming. It means long days away from home and treks into remote locations. And it’s not just in the Winter. The busy season is in the Summer when the go to check on the nearly 200 automated sites to repair them or check their logs.
Luckily NRCS gets help from a large array of cooperators. Partners such as Colorado Division of Water Resources, Denver Water and reservoir operators who all collect data and give it to NRCS.
And there’s one other thing to add to the list of things in which NRCS plays a roleunderstanding Climate Change. Snow surveys date back to the 1930s when the Dust Bowl got the West’s attention about the need to protect soils in a region with a limited water supply.
Mage: The Snow Survey program is the only program that has been doing snowpack monitoring for this long and this consistently. So that long term record is huge for climate studies. The Colorado Climate Center actually is another one of our stakeholders who use our data probably daily.
Jamie: Whether you want to know the short term forecast— like how the conditions are at your favorite back country ski area or whether or not to plant a garden; or you’re more concerned about our changing climate; think of Mike and Butch. They’re out there, no matter what the season, no matter what the weather, chasing the data that will affect your daily life. 💧
[ Music: Orouni - Snowfall With A Sock, Creative Commons ]
Snow Survey Website
Published: March 2014 © Copyright H2O Media, LTD.