During this snowy February, I have enjoyed checking the Lamoille Canyon No. 3 snotel site. I watched the snow build up to 50-inch depth at its 7,700-foot elevation. After each snowstorm, the depth would increase and in between storms, the snow level would slowly drop. I could also look at a map of snotel sites along the Ruby Mountains, and check spots like Fry Canyon at 6,600 feet elevation (13 inches of snow), and Lamoille No. 5 at 8,700 feet (80 inches).
Snotel (snow telemetry) sites are automated data gathering sites that replace the old snow course surveys. Dr. Church of the University of Nevada set up the first snow course on Mt. Rose outside of Reno in 1906. In 1919, he set up snow survey sites in Elko County.
Because of the drought creating the dust bowl, in 1935, Congress appropriated $15,000 to the Bureau of Agricultural Engineering to conduct snow surveys for the purpose of forecasting irrigation water supplies. Snow surveys now take place across the West.
Gerry Miller remembers doing hundreds of snow course surveys from 1981 to 2011. He worked for the Natural Resource Conservation Service. It took snowshoes, skis, snowmobiles, Tucker snowcats and helicopters to reach the survey sites.
A snow survey site is about 1,000 feet long with five to ten sample points. Long aluminum pipes were thrust into the snow until they touched soil. That gave the depth of snow. The retrieved pipe, packed full of snow, was weighed and that gave the amount of frozen water in the snow (the theoretical amount of water melting out of the snow).
The amount of water in the snow is much more important than its depth. Lamoille No. 3’s snow depth of 50 inches, and 31 percent snow water equivalent, means this will melt down to about 15 inches of water.
Today, snotel sites gather the data automatically. A “pillow” laid on the ground collects snow. Its weight tells the weight of water in the snow, using a pressure transducer. A laser positioned above the pillow measures the snow depth.
The sites may have gauges measuring temperature, liquid precipitation, soil temperature, soil moisture, wind, humidity, and barometric pressure. Sites also have solar panels, equipment sheds and antennas that send in data several times each day.
Each summer, personnel visit snotel sites for maintenance. Winter visits are still required at the few snow courses still being used, but also for ground truthing the snotel data by checking the snow depth manually and for emergency repairs.
Of the 947 snotel sites across the continental United States, the Ruby Mountains have six snotel sites and three snow courses. More snotel sites gather data north of Elko.
This snow data is provided to the public and is used to forecast spring and summer water runoff. This tells the amount of water users can plan on for that summer. It gives a good idea of the amount of available water but not the timing of that snow melt. It is harder to predict the timing of the peak runoff and the threat of flooding. Extremes of precipitation, temperature and droughts also throw off water supply forecasts.
To find snotel data, go to nrcs.usda.gov. Under topics, choose water and then snotel and snow courses to get started.