| Posted: 8:39 a.m., Sunday, January 19, 2003 |
Tuckerman Ravine has LOW and MODERATE avalanche danger today. The Little Headwall, Hillman's Highway, The Lower Snowfields and Left Gully have LOW avalanche danger. Natural avalanches are very unlikely and human triggered avalanches are unlikely EXCEPT IN ISOLATED POCKETS. THESE POCKETS DO EXIST. Normal caution is advised. The Bowl, the Headwall, the Lip and Right Gully have MODERATE avalanche danger. Natural avalanches are unlikely and human triggered avalanches are POSSIBLE. Unstable slabs are possible in steep terrain. Use caution in steeper terrain.
Huntington Ravine has LOW avalanche danger. Natural avalanches are very unlikely and human triggered avalanches are unlikely EXCEPT IN ISOLATED POCKETS. THESE POCKETS DO EXIST. Normal caution is advised.
A flow of cold air should persist through the week with a brief repreive tomorrow before the cold returns. These temperatures have caused, and should continue to cause, significant temperature gradients in the snowpack particularly in thinly covered areas. Pockets of brush, rocks, and areas scoured by winds are being influenced most dramatically by the facet growth. We have found very inconsistant results with stability tests due mostly to the depth of new facet growth. Most of the facet growth on southern aspects is occuring above the most recent old ice layer in higher avalanche terrain. This is a concern in areas such as, the climbers left, or SE aspects, near the top of Right Gully. We feel that in this area and others similar to it, such as the Sluice, the Lip, and climbers right of the Chute, could be a problem if a skier or climber finds the right "sweet spot". This "sweet spot" could be a thinner area of the slab over buried brush or rocks. If this occurs, the avalanche triggered could be larger than an isolated pocket. The deeper the facets the more tensile strength dominates and the less your "impact bulb" will effect this weak layer. Basically, the thicker the slab the more the slab will dissipate your weight on the weaknesses beneath. This pertains to what we found digging around on northern aspects yesterday. The thickness and tensile strength of these slabs is a significant factor in the stability of areas on the south side of the Ravine, such as Left Gully. Pockets high in the Right gully and the Sluice had 3-4 cm of 1mm facets beneath 30 to 60 cm of hard slab as of Friday afternoon. Although currently these facets are small, I except them to change rapidly with the consistant high temperature gradients. Some pockets near rock fields and brush have facets from the surface down 30 cms! Keep all this in mind with some new snow coming today and tomorrow. These pockets of deep facets could become buried and be the "sweet spots" for triggering an avalanche. We currently have a tremendous degree of spatial varibility with stability potentially changing several times within a fifty meter area. Even with no new snow the instability may increase if facet growth continues. So... If you are heading into avalanche terrain today be aware that a variety of snow conditions still exist. Realize that avalanche skills are required to travel safely through any avalanche terrain.
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.
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 improving with reasonable coverage. However, be aware that there are still a few problem waterbars and rocks hidden just under the surface.
YESTERDAY WE PUT 11 NEW PICTURES OF SNOW PITS, RUTSCHBLOCK STABILITY TESTS, TUCKERMAN, AND HUNTINGTON ON OUR WEBSITE TUCKERMAN.ORG. SO CHECK THEM OUT!
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