Huntington Ravine CURRENTLY has Low avalanche danger. Natural avalanches are very unlikely and human triggered avalanches are unlikely except in isolated pockets. Normal caution is advised.

Due to the forecasted rain, the snowpack will be trending toward instability throughout the day in all forecast areas. Read on for the details.

Yesterday's field observations found a large range of crusts and slabs, all of which are a factor in today's stability ratings. In Huntington Ravine we found that the winds had scoured out most of the new snow and exposed a crusty layer for the primary surface condition. In Tuckerman there was a surprising amount of icy crust found at the surface with a variety of slab types scattered about, notably on the north side of the Ravine. In Right Gully through the Lip they were as deep as a meter where we were comfortable looking, and they were sitting on the icy crust. These slabs varied in density from pencil to four finger. As usual, if you moved up, down or side to side a few meters, conditions changed. The icy layers also varied from a stratified network of different crusts with some early facets growing beneath them, to beefy crust layers that accounted for a solid 18 cm of the snowpack in those locations. The real question now is how today's precipitation is going to affect stability of the slabs throughout the Ravines. The weather forecast is calling for rain in the mountains today, with the majority of it coming in between noon and 8:00 p.m. We could receive 3/4 to 1" (1.9 to 2.54 cm) of rain by the end of daylight hours. As the low moves over us before dark today, we could see intermittent heavy rain. The snow will be trending toward instability throughout the day. We are primarily concerned about natural avalanche activity today caused by the rain. Areas posted at Considerable have newer slabs on the surface that are sitting on the crust. These are the areas of most concern. Some areas have pockets of slabs, while areas on the north side of Tuckerman Ravine have larger slabs as discussed above. These areas that have the largest slabs will be on the upper end of the Considerable rating and pushing High as we approach the end of the day. Areas posted at Low will quickly jump to Considerable later in the day due to the growing concern of natural avalanche activity. In these areas the rain will have to erode the surface crust and percolate down into the layers below before the concern for natural activity becomes significant. Rain on slabs is rarely a good thing unless your like me and enjoy observing the aftermath of avalanches. Take this as a hint and think twice before you venture into avalanche terrain today.

Tomorrow we expect to be dealing with new snow instabilities. No, this isn't a dream. As this storm system passes and winds shift to the NW, cold air will filter in and allow for this storm to wrap up as snow. This factor, paired with upslope energy, could allow for as much as 6" (15 cm) of new snow in the mountains tomorrow. This will be accompanied by NW winds 60 to 80 mph (96 to 128 kph) and will therefore be loading into both Ravines. The big questions here will be how well the new snow will bond to the old snow that will be getting rained on all day today. This is only the beginning of what is to come in the near future. The weather looks to be very dynamic over the next week. Do not turn your back on it and always be thinking about how the weather is affecting stability!

THE LION HEAD SUMMER TRAIL IS CLOSED DUE TO THE AVALANCHE PRONE SLOPES JUST BELOW TREELINE. THE LION HEAD WINTER ROUTE IS OPEN. Mountaineering skills and equipment are required for safe travel on this route.

The Sherburne Ski Trail is open and has decent coverage though it is thin in places. Expect variable surface conditions as you take the first run on your new board or skis.

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 reading mountain weather's effect on the snowpack, and avalanche rescue. To improve these skills take an avalanche course. We have all the avalanche courses offered in and around the Mt. Washington Valley this winter on our website, tuckerman.org.