What the snow tells us and how we listen
“In the beginning of December, the snowpack was at 69 percent of median and as of today, Dec. 29, 2016, the Roaring Fork Watershed snowpack is at 133 percent of median and the Upper Colorado River Basin is 118 percent of median,” Liza Mitchell of the Roaring Fork Conservancy excitedly told me.
“It was a really dry beginning of winter, and it is not that there have been big storms, but that the storms that have come through have been really wet,” she added.
This change is good news for the Roaring Fork and Middle Colorado watershed. Snowpack, the snow that stacks up throughout the winter in our mountains, is important for our watershed and all the populations that rely on the Colorado River. But how do we consistently get this important information?
SnoTel sites, short for Snowpack Telemetry, collect information on everything from snow depth, to water content in the snow, to the density of the snow. The sites, managed by the Natural Resources Conservation Service, NRCS, are set up on ridges and mountains in remote backcountry areas. The sites transmit the collected information wirelessly through a method called “meteor burst technology.” Basically, the information is sent by radio waves into the sky, bounces off meteorites circling Earth, and down to NRCS stations to be interpreted. No satellites are involved, and no one needs to visit each remote site.
As you probably notice if you ski or play in the snow, not all snow is the same. There are storms that bring in light fluffy snow that is great for skiing, but bad for snowball making (this has a low snow water equivalent, meaning if you melt the snow down, there will be little water) and then there are storms that bring in thick heavy snow (this has a high snow water equivalent, or rather it has a lot of moisture and little air in it). The heavy snow is good for bringing in and storing moisture for our watershed.
Our watershed’s snowpack is closely monitored. Nationally, there are over 730 sites in 11 states. We have eight SnoTel sites alone in our watershed, with seven of these monitoring the Roaring Fork watershed.
The NRCS set up SnoTel sites to collect data remotely in the early 1980s, explained Chad Mickschl, a hydrologist for the BLM, in order “to get better water data for agricultural use, hydropower, irrigation purposes.” The snow water equivalent is an important measurement for understanding how much water will be put back into our watershed to be used throughout the rest of the year.
SnoTel sites track snowpack continuously and provide information for the NRCS to predict how the river will flow for the rest of the year.
“The [flow] forecasts increase in certainty as the winter progresses.” Mitchell, the Education and Outreach Coordinator for the Roaring Fork Conservancy explained. “In May, you have a pretty good idea of the water held in the snowpack, but you can use historical data to predict flow, which is what the NRCS does to generate predictions as early as January and February.”
In the Roaring Fork watershed, the water flow forecasts are based off of rolling 30-year averages, to try and capture more recent landscape changes. Issues do occur when the landscape changes too fast for the rolling averages to normalize them.
Fire, land development, hot weather and dry earth affect snowpack and subsequent runoff predictions. Because these forecasts are so important to people and industries such as agriculture, river recreation and water managers, efforts are in place to study the land changes and make these forecasts more reliable. The NRCS water supply forecasts are incredibly important for decisions surrounding water and we will continue to rely on SnoTel data for the most accurate information.
The Roaring Fork Conservancy generates snowpack reports weekly for the stakeholders in the area based off the SnoTel data. The Roaring Fork Conservancy will be hosting a SnoTel site visit on Feb. 26 to discuss how the SnoTel technology works, its limitations and the importance of snowpack for our region. Visit http://www.roaringfork.org, for more information.
Annie Whetzel is community outreach coordinator for the Middle Colorado Watershed Council.
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