Favored areas have received up to 19 inches of snow with about an inch of moisture since Saturday afternoon. Strong and gusty winds will be forming new soft slabs on leeward aspects. Humans who venture onto steep avalanche prone slopes could trigger these slabs and loose snow sloughs that involve the recent new snow. The new snow and winds have also increased the load on persistent weak layers. This new load is especially significant in areas where the snowpack is shallow and has poor structure. Large persistent slab avalanches could be human triggered with potentially serious consequences. Monitor conditions. Stronger than forecast winds could rapidly increase the avalanche hazard. A careful evaluation of the snowpack and terrain is warranted.
New soft slab avalanches formed by west-southwest winds could be triggered by humans on steep wind loaded slopes. These slabs could be up to two feet deep at the mid and upper elevations. Pockets of wind slabs up to a foot in depth could be human triggered in steep terrain features at the lower elevations.
New snow and winds have increased the load on persistent weak layers. Large slab avalanches 2 to 4 feet deep at the mid and upper elevations and 1 to 3 feet deep at the lower elevations could be triggered by the weight of a person or the release of a wind slab or large loose snow slough.
Heavy snowfall and strong southwest winds are expected overnight with another foot of accumulation possible at the upper elevations by 7 am. A break in snowfall is expected during daylight hours with partial clearing likely before another round of snow begins Tuesday night. Temperatures are to be about ten degrees warmer tomorrow with mountains reaching the upper teens. Slabs will continue to increase in size and sensitivity overnight and natural activity is expected at the upper elevations of the Tetons early Tuesday morning where the avalanche danger rating is expected to increase to High. At other elevations of the Tetons and in the other forecast areas the rating is expected to be Considerable. Human triggered wind slabs will be likely and an increased potential to trigger deeper persistent layers will also exist. Conservative decision making in all terrain is a must and steep wind loaded avalanche starting zones should be avoided.
