Two cold fronts bring several inches of new snow to the mountains
The dry conditions that have prevailed over the region since the beginning of November were interrupted by a fast-moving disturbance that passed through the region in the morning on November 16 and another cold front that moved south from Montana through Central Wyoming into Colorado on November 20. Both systems brought 1 to 3 inches of snow to the higher elevations. Snowfall totals for this week were 5 to 6 inches on Togwotee Pass, 3 to 5 inches in the Teton Range and 3 inches in the Wyoming Range.
In the mountains daytime high temperatures were in the 30’s and 40’s on November 15. They dropped into the 20’s after the passage of the first cold front. They rose into the 30’s and 40’s ahead of the passage of the second cold front and then fell back into the 20’s during the last two days of this week. Winds along the higher ridges and peaks were mostly between 10 to 30 miles per hour and veered from the southwest to the west-northwest then backed to the southwest and veered to the north and east after the passage of the second cold front. Wind gust from 60 to 70 miles per hour were recorded ahead of and during the first frontal passage and from 40 to 55 miles per hour ahead of and during the second fontal passage.
Our early season snowpack is generally one to two feet deep at the higher elevations. Slopes are mostly bare below an elevation of 7,500 feet and on steep south facing slopes up to an elevation of 10,000 feet. Snow surfaces are wind-blown in open terrain. Dry soft snow surfaces can be found in shaded, sheltered areas. The snowpack structure is comprised of a mix of crusts and faceted snow. In sheltered areas where the snow is deepest, crusts are deteriorating and the snowpack is primarily comprised of unconsolidated faceted snow crystals. Thermal crusts play a more prominent role in the snow structure on sunlit aspects and in areas where the snowpack is shallower.
A review of Snotel data indicates the moisture content of the snowpack in Snake River Drainage above Palisades Reservoir was 81% of the 30-year average on November 21. The moisture content of the snow pack at the Grand Targhee Snotel site was 86%. It was 98% at the Togwotee Pass Snotel site and 97% on Blind Bull Summit in the Wyoming Range.