Recently developed storm slabs will increase in depth as the day progresses with both natural and human triggered avalanches possible. While less likely, persistent slabs continue to be a concern and could be very destructive. Careful snowpack evaluation, cautious route finding and conservative decision making will all be essential for safe travel in avalanche terrain this afternoon.
Up to an additional foot of new snow accompanied by very strong southwesterly to westerly ridgetop winds will increase depths up to two feet of recently developed storm slabs from the past two days. At the mid and upper elevations, backcountry travelers could easily trigger these slides in steep, wind loaded terrain. The chance for natural activity will increase as the day progresses.
By the end of the day, storm totals from Friday of two to two and a half inches of snow water equivalent have been added to snowpack. This additional weight may be sufficient to impact persistent weak layers near the base of the snowpack from October. These crusts and faceted snow are present on most upper elevations slopes and dip into mid elevations slopes on northerly aspects. If triggered, these slides could reach depths of two to four feet depending on elevation and will carry high consequences.
Six to twelve inches of new snow is possible in the Tetons overnight. Lesser amounts are expected in the Togwotee Pass and Greys River areas. Snowfall will taper off on Monday with partly to mostly cloudy skies during the day. Strong southwesterly winds at 30 to 50 miles per hour will veer to the west and decrease to 20 to 30 miles per hour by the morning. Overnight lows in the mountains will be in the mid teens before rising to near 20 during the day.If forecasted snowfall occurs, the General Avalanche Hazard is expected to be CONSIDERABLE in the Tetons on Monday. Storm slabs, one to two feet in depth, could be triggered by backcountry travelers in steep, wind loaded terrain. In heavily wind loaded areas, these slabs could also release naturally. Persistent slabs still warrant caution. Even though these are low probability events, they can carry high consequences.
