Avalanche Advisory for Friday, December 21, 2007 at 6:30am By Eric White The Details: This Season: We had a few early season hints of snow, then a dry spell with December starting to show signs of winter. Our precipitation is around 96% of normal. We currently have around 3 feet of new snow on a thin and week old snow surface. We are in a "La Nina" climate condition which often means wetter than normal winters in our area and expectations are above normal precipitation into the spring. Weather Observations: We currently have limited remote weather station data. Some of our coldest temperatures of the season have arrived in a few areas like McCloud at 12F and Mumbo Basin at 3F! Mt. Shasta - We have 42 inches of snow on the ground near tree line with around 2 inches of new snow over the last 24 hours. The snow settled 3+ inches overnight. In the last 24 hours temperatures have ranged between 8F to 23F at 7000 ft. and it is currently 8F. Winds this morning at tree line were estimated at around 28 mph from the NW, and light and variable below tree line. On the upper mountain winds have slowed this morning to around 50 mph from the NW. Castle/Mt. Eddy - Mt. Eddy received around 3 inches of new snow in the last 24 hours with 2 inches of settlement. Temperatures were between 11F to 25F over the last 24 hours. We estimate around 3 feet of snow on the ground. We currently have partly cloudy skies. Weather Forecast: We will have a break today and great winter weather, with light winds and cool temperatures. We will be at the bottom end of the next 2 storms with only light precipitation expected. A weak cold front will arrive tomorrow mid morning and bring only a dusting to 3 inches of snow. Another cold front will arrive Sunday evening and continue into Monday. Most of Christmas will be dry with a storm arriving in the evening. For today we can expect partly cloudy to clear skies with temperatures at tree line warming into the teens to 20F. Winds below tree line will be light and variable and at tree line winds will be 15-20 mph from the NW. On the upper mountain winds will slow today from 45-50 mph to 25-30mph from the N/NW. By tomorrow morning, winds will move to the SW. Snow Pack: We have had 3+ feet of snow fall over the last week, most of it landing on a thin snow pack. Natural avalanches were reported earlier this week. My concerns today remain with wind loaded slopes, mostly at and above tree line. During the storm (Mon-Thur) most of the loading was on N and E aspects. Last night at mid and upper elevations, N winds loaded S and E aspects. With a variety of wind loading over the past few days, you will need to be observant for clues to the most recent loading (S and E aspects). Some wind slabs will be pretty touchy while others will be hard to break and that leads to a little bit of uncertainty with stability in N, S and E aspects, SO, continue to use caution and be observant today, enjoying the best conditions in the trees. Watch for shallowly buried rocks, sticks and logs and snow collapsing near trees and brush. Some important thoughts: This advisory does not apply to Ski Areas or Highways and is for the Mt. Shasta, Castle Lake and Mt. Eddy back country. Use this information for guidance only. You may find different conditions in the backcountry and should travel accordingly. This advisory expires at midnight tonight. As always, use safe travel practices: travel with a partner, travel one at a time in suspect areas, go from one island of safety to another, choose safe routes, wear a transceiver, carry a shovel and probe, and know how to use your gear!