Tuckerman and Huntington Ravine have CONSIDERABLE avalanche danger today. Natural avalanches are POSSIBLE and human triggered avalanches are PROBABLE. Unstable slabs are probable in steep terrain. Be increasingly cautious in steeper terrain.

The summit received 3.7 inches (9.5 cm) of new snow in the past 24 hours with 4.4 inches (11 cm) in the past 48 hours. Winds never shifted yesterday and held out of the W around 50 mph (84 kph) as of 800 am Sunday morning. As the day progressed light snow and showers occured every hour with diminishing winds. Between 8pm and midnight winds were still out of the W, but only blowing in the teens. Around 1:00 am they began increasing slowly to the current NW wind at 32 mph (54 kph). There is a strong gradient so I expect winds to pick up quickly with the entry of the arctic air moving into the area as we speak. Summit temperatures are plumeting and are currently at -15 degrees F (-26 C). Winds are forecasted out of the NW at 60mph (100 kph) today, but it wouldn't surprise me if they get higher. These strong winds will move the light 5% density snow from the past 2 days pouring into the ravines. Light snow moves very easily so I expect significant loading to occur through the day as winds increase. Winds yesterday morning brought in soft slab which became softer and less cohesive as winds diminished into the overnight. As winds increase a denser slab will build over this less cohesive layer. Anticipate the instability and avalanche danger to increase through the day. On larger snowfields in the lee of NW winds such as under the Headwall and Lip in Tuckerman I would expect the avalanche danger to be on the upper end of Considerable. Due to light density snow moving so easily stability will vary based on exposure to the wind. Strong lee areas will probably load with deep new snow while other areas will become blown clean. Keep this in mind as you venture through the mountains into the next couple of days. The arctic air should slow the slab sintering and consolidation process so anticipate unstable slabs to persist through the cold snap. In snow pits dug on Saturday afternoon under the Lip, Right gully, and Right Right gully we continued to find the faceting we have been watching for about the past 2 weeks. We found 1.75 and 2 mm facets between 60 and 120 cms down from the surface between several ice layers. The varing facet depths are due to spatial variablity of different lee loading depths from pocket to pocket. Early facets were found much closer to the surface, but were also quite variable. The tensile strength of the hard slab above these layers are holding the snowpack together beneath todays new loading. However, if avalanche activity occurs from new loading it is possible for it to step down to these facet layers. We will keep an eye on this developing problem.

Natural ice dam releases occured in Pinnacle gully and Odell's over the weekend in Huntington Ravine. Expect the continued temperature swings to contribute to the dynamics of ice instability. Rock protection is always a better option in these circumstances over ice screws.

THE WINTER LION HEAD ROUTE IS OPEN. The route leaves from the Huntington Fire Road and has orange signs starting on the Tuckerman Ravine trail at roughly the 1.8 mile mark. It is a steep and challenging route. Crampons, an ice axe, and the ability to use them with skill are required for safe travel. Avalanche skills are always required to travel safely in the mountains. Be prepared to do your own stability assessments.

The John Sherburne ski trail is once again improving. Be aware that there are still a few problem waterbars, rocks, and hidden branches from last weeks big wind just under the surface.

AS ALWAYS, THIS ADVISORY IS ONE MORE TOOL TO HELP YOU MAKE YOUR OWN DECISIONS IN AVALANCHE TERRAIN. It should be used along with your own snow stability assessments, knowledge of safe travel techniques, skill in mountain weather's effect on the snowpack, and avalanche rescue.

United States Avalanche Danger Descriptions. ÷