All areas in Huntington Ravine have CONSIDERABLE avalanche danger today. Natural avalanches are possible and human triggered avalanches are probable. Unstable slabs are probable on steep terrain. Be increasingly cautious in steeper terrain.

Another (yes another) wintry mix is upon us on Mt. Washington. Today's forecast is calling for 2.5 to 7.5 cm (1-3") of new snow to fall before changing to freezing rain and sleet. This change over should occur in the early afternoon hours. With warm air aloft, the higher summits are going to see this change over before the valleys do. Winds will become S and SW and increasing to 45 to 80 kph (30 to 50 mph). After the change over to sleet and freezing rain we can expect an additional .6 cm (.25") of water equivalent to be added to the snowpack. This weather combined with recent weather events leaves us concerned about stability in a variety of ways. All of which conclude in Considerable avalanche danger with natural avalanche activity being possible. In recent days new snow has been loaded into both Ravines, especially from Monday morning through Tuesday mid-day. This loading caused some natural avalanche activity to occur in Hillman's Highway and O'Dells. Other activity may have occurred, but further loading has erased any evidence. This activity confirms that the snow has been unstable and any slabs that have formed recently are suspect. Yesterday's field observations determined that these slabs existed on a most aspects and, as we have discussed many times, they are sitting on a slippery crust which does not provide a good surface for new snow to bond with. Today we will see new snow in the morning adding weight to the existing slabs, followed by sleet and freezing rain, which will add even more weight to the slabs. It is hard to know what the critical amount of precipitation is needed to tip the balance of strength vs. stress. Today's precipitation could be enough. S and SW winds will also play into today's stability as they have the potential to move today's new snow into lee areas. Expect loading to occur on N and NE aspects and cross loading to occur on others. Hillman's Highway, Left Gully, the Escape Hatch, South Gully, O'Dells and Pinnacle are all candidates for direct loading from southerly winds. As mentioned, cross-loading could occur in other areas, notably the Bowl and Central Gully.

While most areas share a common rating today, it is worth noting that they don't all share the same potential and problems. The rating descriptor, "natural avalanches are possible and human triggered avalanches are probable" fits for all of the areas for different reasons. The Bowl and Lip are already at this rating and could be on the upper end of Considerable later today. The Lower Snowfields don't have much potential on their own but are in the run out of any activity that occurs in the Duchess. Areas that had recent activity are less of a concern now but are in the direct lee of today's forecasted winds. Southerly aspects won't see as much loading today but will still receive additional weight on top of existing slabs. One thing they all share is a slippery crust that provides and ideal sliding surface for snow.

The crust that remains exposed at the surface in different places varies tremendously in hardness. Some locations have gone through so much age hardening that self arrest will be extremely difficult if not impossible in the case of a fall. Expect all surface crust to be very hard until proven otherwise. All visitors traveling on steep terrain should be prepared with crampons and an ice axe.

THE LION HEAD WINTER ROUTE IS OPEN. Mountaineering skills and equipment are required for safe travel on this route. The John Sherburne Ski Trail has improved dramatically with new snow. You should still expect hidden hazards in the form of turf, rocks, bushes and deep waterbars lurking under the new snow cover.

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.