Sawtooth Avalanche Report | Sports

In our last avalanche report, Ben talked about our third multi-day storm cycle of the winter. Since then we have moved into a long period of high pressure, bringing good weather and no new snow. Before I talk about how this weather pattern changes avalanche conditions, I want to take a moment and highlight the last month. It was simply breathtaking. The period from December 11 to January 11. 7 is the snowiest I can remember in my 17 years here. During this period we had three separate multi-day storm events that each dropped 2-4 feet of snow. We had other dribs and drabs between these storm cycles. On December 10th things were dark and our snowpack was around 60-80% of average. Going forward, our snowpack jumped to 140-160% of normal in less than a month, which made for great skiing, great for summer water needs, and great for snow removal companies. Everyone wins. So how much snow did we get? It is difficult to accurately measure snowfall during multi-day storms. Remote weather station snow sensors measure both snow depth gain (snowfall) and snow depth loss (settlement). These two processes occur simultaneously during large storms, the main source of inaccuracy. One thing we can do is look at the amount of snow water equivalent (SWE) that has accumulated over a period of time. Most of our remote weather stations measure this accurately. First of all, what is SWE (pronounced “swee” by snow nerds). If you put a bucket in your yard during a snowstorm, scoop up 10 inches of fresh snow, then bring it inside to melt it, that would leave you with the SWE. If it melted up to 1 inch of liquid water, that amount of SWE would mean that the snow density is 10%. For reference: 4-5% snow is super fluffy powder, 8% is average for our area, and more than 10% tends towards denser new snow. Using an average snow density and a measured SWE, we can arrive at an estimate of snowfall for the month period in question. For the calculations, I use an average density of 8%, which seems reasonable (and probably conservative). Here are the estimated snowfalls since December 11 at a handful of local stations: Baldy—90 inches; Galena Summit—130 inches; Vienna Mine—180 inches. All that snowfall never gave our snowpack the break it needed. As the deep weak layers of the snowpack received an almost continuous load, dangerous avalanche conditions resulted. It has now been a week since the snowfall has ended and the snowpack is taking a well-deserved rest. As a result, the avalanche danger decreased and we started to see more yellow and green in the avalanche forecast than orange or red. Corn moo danger does not mean no danger. The triggering of avalanches becomes improbable, but not impossible. Be sure to read the finer details in the daily avalanche forecast whenever you head into the backcountry for a day of skiing or hiking. Thanks for reading and enjoy the sunshine.(tncms active)85e6aac6-6e66-11ec-9679-fb49bcc2af2b[0](/tncms-asset)(tncms-asset)ae88d5a8-6e66-11ec-8713-cf8303142181[1](/tncms-asset)

Sawtooth Avalanche Weekend Update

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