This time of year, the Snow Safety crew spends a great deal of time looking at the changing impact Spring and early Summer have on the snowpack. Warming conditions lead to melting snow and, ultimately water running through the snowpack. Depending on the condition of the snowpack, the running water can significantly weaken the snow and lead to "wet snow avalanches." Just prior to conditions that cause unstable snow, we like to close steeper terrain to minimize the chance of people getting caught in wet snow avalanches.
While not a direct forecasting element of avalanche instability, we pay close attention to stream flows around us. Now, by chance, many team members are rafters and kayakers and are already paying attention to streamflows. A big increase in streamflows this time of year clearly means a lot of snow has turned to water and is flowing downhill. Below is a graph from our local Snake River. Over the last week, its flow has increased by about 340 percent. That increase clearly indicates a change in the snowpack.
