Guess what....it's snowing again! A winter storm warning is in effect for today with a variety of precipitation types expected throughout the day. It is currently snowing at a steady rate with 2.4" (6 cm) of accumulation so far at Hermit Lake and 3" (7.5 cm) at the Harvard Cabin. Snow is expected to change over to ice pellets later this morning as warm air aloft invades the mountains. There is a lot of moisture associated with this system and 6 to 10" (15 to 25 cm) of frozen accumulation could pile up today. Unfortunately, we may also experience some freezing rain and even rain up here before the precipitation changes back to snow as the storm pulls away. Summit winds are currently out of the south in the 50 mph range and forecasted to shift to the west with speeds between 45 and 65 mph (72 and 105 kph) with higher gusts. This concoction of weather will create a number of stability issues that result in High avalanche danger in most forecast areas.

The first stability concern of the day is loading of the new snow into lee areas. This will create instabilities primarily on north and east aspects while winds are out of the south. As the precipitation type begins to change, an upside down snowpack will develop with lighter snow underneath denser snow and ice pellets. This scenario is not aspect biased so all forecast areas will see a rise in instability as the precipitation changes over. This alone warrants a High rating in most areas and caused us to bump the Little Headwall to Considerable. If we see rain on the new snow today, that will also serve as a good trigger for new avalanches. If we see a period of freezing rain, the new snow may become encapsulated above treeline which will inhibit wind transport today. Until then, wind transporting will be a significant factor throughout the day with south winds shifting to the west and depositing a lot of new precipitation in the Ravines. Today's stability concerns are focused on what is occurring as a result of this storm but there are other stability issues out there. These issues are in the form of hard slabs that developed during our last big avalanche cycle on Sunday and Monday. While I am not too concerned about these moving on their own, I think new avalanches could step down into these harder slabs. The Lip, Sluice and Headwall stand out as the most likely candidates for this to occur.

Now that we have covered the details of snow stability today, we should step back for a moment and look at the big picture. This season is giving us some dramatic avalanches and some of our paths are running way bigger than normal. During our last cycle on Sunday and Monday, Hillman's Highway ran bigger than I have ever seen it go in the ten years I have been paying attention to avalanches on Mt. Washington. This avalanche cleaned out a swath of mature forest in its runout with trees around 60 years old uprooted, snapped and tossed around like toothpicks. The Escape Hatch also cleaned out a bunch of trees and other avalanches in Huntington filled in the base of the Ravine to make it feel more like the floor of Tuckerman. These large avalanches are paving the way for the next big cycle to run even farther. Well developed start zones in many of our forecast areas means that avalanches will be more common as there are less anchors to keep the snow put. We also have a lot more avalanche terrain now. Snowfields all over Mt. Washington and the Presidentials are developing and avalanching. Chris observed fracture lines all along the eastern side of the Presidential Range yesterday. We observed activity around the Ravines in unusual areas including tree covered gullies and snowfields. File this information into your brain to use as you are traveling in the mountains this winter. Expect avalanche terrain in areas you don't usually see it and expect avalanches to exceed their normal track lengths during avalanche cycles.

As always, crampons, an ice axe, and solid self arrest skills are recommended for travel in steep terrain. This includes the Lion Head Winter Route. The Sherburne Ski Trail is open with full coverage and new snow.