Posted 8:30a.m., Tuesday, February 15, 2011
Tuckerman Ravine has Considerable avalanche danger today. Natural avalanches are possible and human-triggered avalanches are likely. The only exception to this rating is the Little Headwall which has Low avalanche danger. Natural and human-triggered avalanches are unlikely in this area.
Huntington Ravine has Low avalanche danger. Natural and human-triggered avalanches are unlikely. Watch for unstable snow on isolated terrain features.
Our relationship with the mountain is love-hate in so many ways. Yesterday she decided to show us a little Valentine’s Day sweetness by not developing another crust layer as you will now find at most lower elevations. The warmest air of the day came in the morning as we were working on the advisory but the mercury soon dropped just enough to allow the ravines to move back below the freezing mark. When precipitation moved in during the late afternoon there was a hint of liquid in the air but it soon changed to graupel and then straight snow. The summit picked up 1.7″ (4.3cm) of new 6% snow while we measured around 4″ (10cm) at both the Hermit Lake and Harvard Cabin snowplots. The measurements are somewhat questionable based on the amount of wind effect we’re seeing and the Tucks Trail was heavily drifted in this morning. On the other hand my gut was telling me that we received more snow than the summit reported so 4″ might be accurate. Not getting rain in the ravines was great but additional new snow really reminded us of why we fell in love with this rockpile.
Then there’s the wind…the hateful, punishing wind. While it blew out of the W for the majority of the day yesterday it eventually made the wrap to the NW after dark and began to blow with the fury of a lover who got the boot on Valentine’s Day. Speeds have already pushed over 100mph (161kph) this morning and are forecasted to gust upwards of 120mph (193kph) as the day moves along. These conditions have likely scoured many areas including the majority of Huntington Ravine hence the Low rating. Despite this rating we expect that you will find isolated pockets of new hard windslab in Huntington especially in well protected areas such as the lower portions of the gullies and upper part of the Fan. In Tuckerman the wind direction and speed have likely caused some scouring where terrain features squeeze the wind through constrictions such as upper part of Left Gully. Historically this happens to a far lesser degree than it does in Huntington. With a couple inches of new snow (if not more) combined with what existed from days past I expect that we have developed widespread hard windslab in Tuckerman’s forecast areas. We’ve seen some high winds over the past week but nothing quite as strong as today and they’ve mostly been out of the W. The higher speeds with a NW origin will allow snow to be ripped up from alpine areas where it was formerly safe. As it is deposited in Tuckerman Ravine it is being laid down on top of existing layers of windslab that have caused ratings to be elevated for the past week. Some of the areas in the direct lee of today’s winds such as the Lip haven’t seen a Low rating since January! With all this in mind we expect to see natural avalanche activity occur today in Tuckerman Ravine and believe that new cold windslab will be reactive to human triggers.
Today’s arctic temps will allow potential energy to remain in the new snow. They’ll also remind you that the mountain often shows no love for her suitors. It is currently -18F (-28C) at the summit with winds gusting over 115 mph (185kph). If you’re planning on a summit bid today I’d recommend staying in the valley and going shopping for all the leftover, half-price chocolates. The mountain won’t miss you.
- Safe travel in avalanche terrain requires training and experience. This advisory is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
- Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast. For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or the Harvard Cabin.
- This advisory expires at midnight. A new advisory will be issued tomorrow.
Justin Preisendorfer, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856