8:54 a.m., Saturday, January 11, 2003 WE NOW HAVE ALL OUR BULLETINS ARCHIVED SO YOU CAN SEE THE AVALANCHE TREND AS FAR BACK AS YOU LIKE. SCROLL TO THE BOTTOM OF THIS PAGE AND CLICK ON ARCHIVED BULLETINS. Tuckerman Ravine has MODERATE and CONSIDERABLE avalanche danger today. The Little Headwall has MODERATE avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Use caution in steeper terrain. All other areas in Tuckerman have CONSIDERABLE avalanche danger. Natural avalanches are possible and human triggered avalanches are probable. Unstable slabs are probable on steep terrain. Be increasingly cautious in steeper terrain. Huntington Ravine has MODERATE and CONSIDERABLE avalanche danger. Central Gully has CONSIDERABLE avalanche danger. Natural avalanches are possible and human triggered avalanches are probable. Be increasingly cautious in steeper terrain. All other gullies in Huntington Ravine have MODERATE avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Use caution in steeper terrain. The summit received another 2" (5 cm) of snow over the past 24 hours. This adds up to about 7.5" (19 cm) in past 72 hours with winds between 30-80 mph (50-133 kph) from the NW, WNW, and W. This new snow, in addition to all the snow movement from last weekends storm, has brought in a significant amount of loading on many aspects. There are variable stability conditions out there today within the same danger rating. E, SE, and S aspects are picking up the most new snow due to the current and forecasted winds. So realize that even though multiple areas fall under the appropriate definition of Considerable the stability varies. Snow showers are forecasted through the weekend so be prepared for an increasing avalanche danger. Be aware that most areas with a call of Moderate and Considerable are on the upper end of the rating and close to bumping up a rating. Loading will continue through the day so put your avalanche eyes on high alert. With very low visibility you may not see people above you who could trigger a slab avalanche. This is particularly true on a weekend when there are more triggers wandering all over the mountain than usual. Cold temperatures will slow the settling and sintering rates of the snowpack. Expect unstable slabs found today to persist through the weekend in many locations. Some of the gullies between Lion Head and Right Gully picked up so much new snow from last weekends storm that you need to pay attention to stay on the Lion Head trail when going towards the summit. It is possible in a few locations to wander into avalanche terrain just 10 meters south of the trail cairns. This is something to keep in mind through out the winter. AS OF 7:30 THIS MORNING THE TEMPERATURE ON THE SUMMIT IS NEGATIVE 15 WITH WINDS FORECASTED FOR OVER 70 MPH. SO BE PREPARED FOR FULL ARCTIC CONDITIONS. YOU WILL NEED HIGH QUALITY ARCTIC MOUNTAINEERING CLOTHING AND EXPERIENCE TO TRAVEL SAFELY ABOVE TREELINE TODAY. TRAVELING ALONE IS NOT A GOOD IDEA. ONE SMALL PROBLEM LIKE AN UNTIED BOOT CAN DOMINO INTO A DIRE AND UNFOURTUNATE SET OF CIRCUMSTANCES. We left off yesterday with a discussion of the up and down nature of the avalanche rating in an Arctic-Maritime Climate. Today we'll briefly tie that into Direct action avalanche activity. 95-99% of our avalanche activity is due directly to current weather and weather over the past 2-3 days. New snow, sun, wind, rain, warm air mass, etc. We very rarely have widespread long persistant weaknesses in our snowpack such as buried surface hoar or depth hoar growth that doesn't become moot by "bridging". Bridging here in the northeast is primarily when the tensile strength of the layers over the weakness is so strong it negates weaknesses under the slab. This may be an extremely firm hard slab packed by high Mt. Washington winds. Or as discussed yesterday 2 inches of rain followed by arctic temperature can create a thick ice layer as hard and as strong as concrete. In the event that another set of weather comes in and melts this concrete the buried weakness may now become an issue. So there aren't any "absolutes" in the art of avalanche predictions. Avalanches occuring on these buried weak layers without significant weather events would be an example of "Indirect" avalanche activity which in the U.S. is more of a western problem. We'll get into that tomorrow. 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 mountain weather's effect on the snowpack, and avalanche rescue. THE WINTER LION HEAD ROUTE IS OPEN. The route leaves from the Huntington Fire Road and has orange signs starting on the Tuckerman Ravine trail at roughly the 1.8 mile mark. It is a steep and challenging route. Crampons, an ice axe, and the ability to use them with skill are required for safe travel. Snow fields are growing particularly near treeline just off the winter route. As winter progresses these will increase in size causing possible avalanche activity. Avalanche skills are always required to travel safely in the mountains. Be prepared to do your own stability assessments. The John Sherburne ski trail has improved with this past storm. There are a few problem waterbars and rocks still hidden just under the new snow. PLEASE REMEMBER: o Any new precipitation may increase the avalanche danger, this includes wind transported snow. Obtain latest weather forecast before starting out. For more information, contact the U.S. Forest Service Snow Rangers: AMC at Pinkham Notch Visitor Center or Hermit Lake Shelters. THIS AVALANCHE BULLETIN WILL EXPIRE AT MIDNIGHT. Christopher Joosen, Snow Ranger USDA Forest Service White Mountain National Forest