Over the past 24 hours the weather events have been wicked. Yesterday the Summit received 3.8 cm (1.5") of rain, which appears to have triggered some avalanches in the Ravines. This rain was pushed out by a cold front and temperatures have dropped from 7 C (44F) to -12C (10F) at Hermit Lake. This rapid freeze had created an impressive temperature gradient in our snowpack. The rain carried warm air deep into the snow. This mornings snowpack observations in Huntington showed a surface temperature of -10C, a T-10 (temperature 10 cm down) of -3.5C and a T-20 of -0.5C. I was surprised to see that all of this snow had already recrystallized. With this cold snow on top and warm snow below we should see some outstanding facet growth over the next couple of days.

If you are heading into the mountains you should be prepared for some interesting conditions. Ice climbers should be weary of ice dams, undermined ice and snow and running water over the ice. Mountaineers should be ready for very icy snow slopes with the potential for long sliding falls to occur if self-arrest is not achieved quickly. Off trail explorers should certainly have snowshoes, otherwise you probably won't get very far due to the breakable crust. Hikers should have ski poles and crampons for packed trails, as they are unusually slippery. And finally, skiers and boarders who plan on heading to Mt. Washington should consider another activity.

THE LION HEAD SUMMER TRAIL IS NOW CLOSED DUE TO THE AVALANCHE PRONE SLOPES JUST BELOW TREELINE. THE LION HEAD WINTER ROUTE IS OPEN. Mountaineering skills and equipment are required for safe travel on this route.

The John Sherburne Ski Trail is very slick due to recent rain followed by freezing temperatures. The rain has also exposed more rocks, bushes and waterbars.

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 reading mountain weather's effect on the snowpack and avalanche rescue. To improve these skills take an avalanche course. We have all the avalanche courses offered in and around the Mt. Washington Valley this winter on our website, tuckerman.org.