Tuckerman Ravine has CONSIDERABLE and MODERATE avalanche danger. Natural avalanches are possible and human triggered avalanches are likely in Lobster Claw, Right Gully, the Sluice, the Lip and the Center Bowl which are rated Considerable. Careful snowpack evaluation, cautious route finding and conservative decision making is essential. The Chute, Left Gully, Hillmans Highway, and the Lower Snowfields have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. The Little Headwall has Low avalanche danger. Natural and human triggered avalanches are unlikely there.
Huntington Ravine has CONSIDERABLE avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. Careful snowpack evaluation, cautious route finding and conservative decision making is essential. The only exception to this is the Escape Hatch which is Moderate. Natural avalanches are unlikely and human triggered avalanches are possible.
Yesterday we received 2.4″ of snow, most of which was heavily rimed snow and graupel. This snow fell on light E winds and coated slopes in the 30-40 degree range and sluffed off of and pooled beneath steeper areas. Field observations yesterday led several parties of skiers to turn around after encountering large areas of pooled graupel over these harder slabs of questionable strength. In Huntington Ravine, many thin fracture lines in this new soft slab were observed this morning indicating that many of these features avalanched naturally, most likely overnight and early this morning as the winds ramped up and shifted directions. So far, we have observed fracture lines in the Duchess, Dodge’s Drop, and Cathedral in Tuckerman and given the wind transported snow we are seeing from Hermit Lake, it won’t be surprising to see natural avalanche in the thin slab releasing in the Considerable rated gullies which are facing south (Lobster Claw, Right Gully and the Lip).
The lingering concern in my mind after off duty field time yesterday in Hillmans Highway and Gully #2 in the Gulf of Slides is the potential for the new snow and windslabs so step down. The pooled graupel areas are currently being wind loaded again in some areas, and could gather enough mass and entrain enough snow to step down and break the weak interface which exists in the 6”of snow that formed windslabs of the softer variety over the last four days. These older slabs, which were only of fair stability, will be further stressed as wind speeds ramp up higher than they have been in several days and add the weight of new more sensitive wind slabs resting on the weak graupel (rimed ball bearing like crystals). I think this step down potential is remote, but it exists and should enter your decision making process if you are moving around in avalanche terrain. The challenge today is predicting exactly when and if natural avalanches will happen. Right now were are teetering in a semantic gray area between unlikely and possible naturals so factor that into your decision making process. One more factor to consider is that we are observing wildly variable wind directions in the ravines even though summit wind vanes are steady ENE so expect Moderate areas to be solidly at the upper end of their rating.
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. Posted 8:40am, March, 8th 2013. A new advisory will be issued tomorrow.
Frank Carus, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856
So far March has sprinkled a little over 8 inches of snow on the summit. Our snow stake near Harvard cabin is just below the 120 cm mark, which is low but not way off a normal season. The big difference seems to show it’s face in both ravines, lots of ice bulges, rock slabs and bushes still showing when most years they are well covered by now, especially low in the run out zones. We seem to be trapped in this trace to 2 inch cycle, day after day. Up-slope events seem to be more common than a big dump of wet heavy snow this year. This ends up leaving the avalanche cycles less frequent and smaller. Which equates to less snow (debris) in the floor of Tuckerman Ravine or in the fan of Huntington Ravine. This does a couple things, makes the run outs more dangerous and makes the late season conditions a bit less reliable. So, with only 12 days left till the vernal equinox mother nature better seriously ramp up the snow production so we can fill in some of those thin spots. What makes it a little worse is to have the constant reminder of the photos in the snow rangers quarters at Hermit Lake taken back in “The Day” showing an almost continuous snow slope from the floor of Tuckerman down the Little Headwall into the Lower Snowfields – not a tree or bush showing. Ahh back in “The Day”.
Just a quick side note: Looks like The Washington Post is getting into the snow storm naming game. This is right off their blog.
Like or hate storm names, Snowquester sure beats “Saturn”, the arbitrary, meaningless name given to the storm by The Weather Channel. So let’s roll with Snowquester … an original, fun, and fitting label for a Washington, D.C. winter storm in March 2013.
Important disclaimer: The fact that we’ve named the storm doesn’t guarantee snow… (in fact, we probably just jinxed the storm!)
It does appear that the whole naming idea has pushed a lot of these storms further south, leaving us with bits and pieces to scrape off the table (wow, I need a good storm to hit us!) The snow this week left us blanketed with around 6 inches all over the terrain due to the lack of our usual high winds. This morning the wind speeds cranked up a bit, tickling the 80 mph mark with gusts but the brunt of the winds coming in around 60 mph. Our time in Huntington Ravine this morning went from relative calm to snow devils, blowing snow and trees shaking off their coating of snow within a matter of minutes. The unstable nature of the winds created some cross-loading up and down the gullies and in unusual places, not just the lee of our prevailing NW winds. Here’a short clip showing snow blowing almost due east while the summit is reporting ENE wind directions, showing how winds can wrap around in unusual ways in each of our ravines. It might also get us a Golden Globe Award?
So if you’ve made it this far into the reading you’re probably interesting in what’s going to happen this weekend? Looks like……..Mid 20’s and mostly sunny for Saturday and partly sunny for Sunday mid 20’s again, both days winds in the 15-30 mph range and maybe down to 10 mph tomorrow. Hold on, before you jump into spring skiing mode we’ve got lots to talk about with the snow pack and what happens when you go from cloudy and cold to sunny and warm. Our snowpack is layered like some fancy cake you get on your 50th birthday. It’s got a few sun-crusts that layered with some softer layers between, even a smattering of graupel in pockets, capped off with a harder, denser wind slab that has been developing throughout the day. So picture your birthday cake that has been sitting on the picnic table in the hot beating sun while your crazy uncle has been talking your ear off about sequestration. Those sweet layers started to melt, get weaker, and when you disturb it, those layers slide off the plate onto your new blue suede shoes. That’s what we’ll be talking about in more detail in tomorrow’s advisory. Not the cake but the potential impact of a rapidly changing snow pack on a warm sunny day. Because none of us want to be the blue suede shoes.
If you’re interested in learning a bit more about up-slope snow events mentioned above be sure to keep an eye out for our continuing series in “The Pit” .
To get the most up to date information be sure to get the advisory tomorrow morning. Have a great weekend and maybe we’ll see you on the mountain.