Posted 8:30 am, Sunday, March 27, 2011
Tuckerman Ravine: Sluice, Lip and Center Bowl have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. All other forecast areas in Tuckerman Ravine have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible.
Huntington Ravine: All forecast areas in Huntington Ravine have Low avalanche danger. Natural and human triggered avalanches are unlikely. Watch for unstable snow on isolated terrain features.
Today’s weather makes it feel like February is just around the corner, not April! A very winter like weather pattern will continue to bring challenging conditions to the mountains today. Summit temperatures are forecasted to max out around 0F (-18 C) and NW winds will remain strong with speeds between 60 and 80 mph (97 ad 129 kph) through the day. The mountain has cleared out and we have been able to see some of the aftermath from recent avalanche cycles. There is a pretty big crown line on the south side of Tuckerman Ravine and remnants of avalanche debris, flanks and fracture lines in numerous other areas. Last night winds ramped up beyond their forecasted speeds with periods of steady 90 mph (145 kph) winds and gusts over 100 mph (161 kph) for several hours. This caused avalanche activity to work its way down to lower elevations including in Raymond’s Cataract, on the Lion Head Summer Trail and a gully located down the ridge from the Escape Hatch in Huntington Ravine. These high winds also scoured out most of Huntington Ravine which is why it is rated Low today but there are still pockets of concern such as the lowest sections of Pinnacle and South. Tuckerman Ravine is a different story. The primary concern here is the Lip and Sluice. The evidence of a recent avalanche on a neighboring slope, the absence of a fracture line in these areas and on-going wind loading is all the information I need to stay the heck away from these forecast areas. Expect unnerving conditions that fall within the Moderate rating in the Lobster Claw, Right Gully and the Chute. Left Gully and Hillman’s Highway fall on the lower end of the Moderate rating. In these locations, wind scouring and packing has left plenty of variability in the snowpack but you may find some parts that are still unstable, especially in the mid-sections of these two gullies and the top climber’s right of Hillman’s. The Lower Snowfields are variable but I would expect to find some pretty reactive snow in this forecast area in protected areas under the buttresses. As for the Little Headwall, you can easily navigate your way though here without too much concern; however, there is a bunch of wind deposited snow on the snowfields at the top of it.
The Lion Head Winter Route is filling in and evidence of recent avalanche activity can be found on both sides of the route. The best route is marked with bamboo poles. Stay on this path to avoid the more significant avalanche terrain on either side.
Snow showers are forecasted to move in this afternoon and linger through tomorrow. At this time, we are not expecting much in the way of accumulation but we will have to see if the mountain can work its magic to give us another 12″ like last week’s snow showers. Wishful thinking?
- 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.
Brian Johnston, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856