Aspen ===== Current Keywords: MODERATE, crowns, facets, human triggered avalanches, natural avalanche, orographics, settle, slab, slabs, surface hoar, trough, weak layer, wind loaded, wind slab, windloading, Mountain Weather and Avalanche Forecast for the Aspen Zone Forecast Issued on 2/20/2008 3:51:41 PM Forecaster: Ann Mellick Weather Synopsis The first in a series of Pacific storms is moving into the state today. Cloud cover is increasing and snow showers have begun on the high peaks in the San Juans. Moisture will continue to spread north, with showers possible in all mountain areas by sundown. This system has a good moisture tap, drawing off the coast of Baja, but weak orographics and moderate lapse rates will keep accumulations on the light side. However, the favored San Juan could pick up a foot by Thursday night. Expect cooler, though mild temperatures and unusually light winds until the trough axis passes Thursday night. A brief break in the weather comes Friday morning before the next trough rolls in. An extended period of unsettled weather promises more mountain snow through early next week. Weather Wednesday Night Thursday Thursday Night Temperature(°F) 12-17 17-22 10-15 Wind Speed(mph) 10-20 5-15 10-20 Wind Direction WSW variable NW->WSW Sky Cover Overcast Overcast Mostly Cloudy Snow(in) 0-3 1-4 0-3 Snowpack Discussion Mild weather and time have helped settle the upper snowpack. However, some surface instabilities persist in recently deposited slabs, especially on east, southeast and south aspects near and above treeline. Observers noted fresh avalanche activity on this layer, Monday on the Highlands Ridge. A skier triggered a small hard slab on a southeast aspect near 12,300 ft in a wind loaded pocket just below the ridge. The slide did not go far but there were some big chunks of hard wind slab in it. A natural avalanche was also observed on an east aspect in the Five Fingers area. Snowmobilers triggered two deep slabs in the neighboring Sawatch zone near Independence Pass on Tuesday. The slides ran on easterly aspects above treeline with crowns ranging from 10-30 feet, leaving up to 50 feet of debris at the bottom of the slope!! Yikes! One rider was caught, though was not in the main flow and luckily walked away uninjured. These slides remind us that deep slabs remain a very real problem; particularly near and above treeline. It may take just the right trigger to release such a slide, but the resulting avalanche could be very large. Rember that the whole season's snowpack remains balanced on top of weak basal facets from early in the season. This is a tricky time because while we are not seeing many slides, the ones that are running are profound. Clear skies and mild temperatures have changed the snow surface. Crusts have formed on sunny aspects and at lower elevations. In the shadier areas we are starting to see some facets and surface hoar forming on top of the snowpack as well. While none of the layers pose a danger today, do take note of their location and distribution as the next storm approaches. Today's surface is tomorrow's weak layer. Avalanche Danger Avalanche danger for the Aspen zone today is MODERATE on all aspects and elevations. Human triggered avalanches remain possible. On all aspects, the most suspect areas are steep slopes with new and recent windloading. The CAIC Aspen office needs your avalanche, snowpack, or weather observations. Drop us and e-mail at [57]caic@qwest.net with any Front Range =========== Current Keywords: LOW, MODERATE, avalanche danger, orographics, settle, slab, slabs, trough, windloaded, Mountain Weather and Avalanche Forecast for the Front Range Zone Forecast Issued on 2/20/2008 3:18:09 PM Forecaster: Ann Mellick Weather Synopsis The first in a series of Pacific storms is moving into the state today. Cloud cover is increasing and snow showers have begun on the high peaks in the San Juans. Moisture will continue to spread north, with showers possible in all mountain areas by sundown. This system has a good moisture tap, drawing off the coast of Baja, but weak orographics and moderate lapse rates will keep accumulations on the light side. However, the favored San Juan could pick up a foot by Thursday night. Expect cooler, though mild temperatures and unusually light winds until the trough axis passes Thursday night. A brief break in the weather comes Friday morning before the next trough rolls in. An extended period of unsettled weather promises more mountain snow through early next week. Weather Wednesday Night Thursday Thursday Night Temperature(°F) 10-15 15-20 7-12 Wind Speed(mph) 5-15 5-15 10-20 Wind Direction W variable WNW Sky Cover Overcast Overcast Mostly Cloudy Snow(in) 0-3 1-4 0-2 Snowpack Discussion No new slides have been reported in the Front Range Zone since the weekend. Mild weather and time have helped settle the upper snowpack. However, some surface instabilities persist in recently deposited slabs, especially on east, southeast and south aspects near and above treeline. Take the time to dig around and check for bonding between upper snowpack layers. Deep slab avalanches continue to be a possibility as well. It may take just the right trigger to release such a slide, but the resulting avalanche could be VERY large and destructive. A skier triggered one such slide on an easterly aspect in Summit County last weekend. Luckily, no one was caught. This is a tricky time because while we are not seeing many slides, the ones that are running are profound. Use caution in exposed, above treeline terrain and slowly work your way onto steeper slopes. Avalanche Danger The avalanche danger in the Front Range is MODERATE on all aspects near and above treeline and LOW on all aspects below treeline. Human triggered avalanches are possible on steep, windloaded slopes, and have the potential to break deeply. Grand Mesa ========== Current Keywords: LOW, avalanche danger, orographics, sluffing, stabilization, trough, whumpfing, wind loaded, Mountain Weather and Avalanche Forecast for the Grand Mesa Zone Forecast Issued on 2/20/2008 3:44:25 PM Forecaster: Ann Mellick Weather Synopsis The first in a series of Pacific storms is moving into the state today. Cloud cover is increasing and snow showers have begun on the high peaks in the San Juans. Moisture will continue to spread north, with showers possible in all mountain areas by sundown. This system has a good moisture tap, drawing off the coast of Baja, but weak orographics and moderate lapse rates will keep accumulations on the light side. However, the favored San Juan could pick up a foot by Thursday night. Expect cooler, though mild temperatures and unusually light winds until the trough axis passes Thursday night. A brief break in the weather comes Friday morning before the next trough rolls in. An extended period of unsettled weather promises more mountain snow through early next week. Weather Wednesday Night Thursday Thursday Night Temperature(°F) 18-23 22-27 15-20 Wind Speed(mph) 0-10 0-10 5-15 Wind Direction variable variable NW Sky Cover Overcast Overcast Mostly Cloudy Snow(in) 0-2 0-3 0-3 Snowpack Discussion Time and warm temperatures have encouraged stabilization in the snowpack. There have been no new avalanches reported from the Grand Mesa area in several weeks, indicating a mostly stable snowpack. The greatest danger in the Grand Mesa Zone continues to be the many small, steep wind loaded slopes and terrain traps. Be sure to evaluate steep slopes before you cross. Watch for signs of instability such as whumpfing noises, propagating cracks, or recent slide activity and avoid slopes where such signs are noted. The avalanche danger will be on the rise once again as snow piles up later this week. Be aware of changing conditions and plan accordingly. Avalanche Danger The avalanche danger for the Grand Mesa is LOW on all aspects and elevations. Watch for sluffing in the new snow and areas of unstable snow on very steep slopes and terrain traps. Please send observations from this or any other zone to [57]caic@qwest.net San Juan North ============== Current Keywords: MODERATE, avalanche danger, crusts, entraining, facets, natural, naturally, orographics, powder , settle, settled, shear, slab, slabs, trough, windloaded, Mountain Weather and Avalanche Forecast for the Northern San Juan Mountain Zone Forecast Issued on 2/20/2008 3:47:49 PM Forecaster: Ann Mellick Weather Synopsis The first in a series of Pacific storms is moving into the state today. Cloud cover is increasing and snow showers have begun on the high peaks in the San Juans. Moisture will continue to spread north, with showers possible in all mountain areas by sundown. This system has a good moisture tap, drawing off the coast of Baja, but weak orographics and moderate lapse rates will keep accumulations on the light side. However, the favored San Juan could pick up a foot by Thursday night. Expect cooler, though mild temperatures and unusually light winds until the trough axis passes Thursday night. A brief break in the weather comes Friday morning before the next trough rolls in. An extended period of unsettled weather promises more mountain snow through early next week. Weather Wednesday Night Thursday Thursday Night Temperature(°F) 12-17 17-22 10-15 Wind Speed(mph) 10-20 10-20 10-20 Wind Direction SSW variable NW->SW Sky Cover Overcast Overcast Mostly Cloudy Snow(in) 3-5 4-7 0-3 Snowpack Discussion Nice weather over the past few days has continued to help the snowpack settle out and gain strength. Backcountry travelers are getting out deeper and deeper into the backcountry and reports from the field indicate very limited avalanche activity. However, a few natural slabs have run near Silverton recently, reminding us that our snowpack has persistent weaknesses and should never be taken for granted. On Sunday, a significant hard slab avalanche ran naturally in Minnesota Gulch up CR110 toward Gladstone. This slide started on a windloaded southeast aspect above treeline. The fracture was estimated at 6 feet deep and 400 feet wide, and it ran to the ground, entraining lots of snow on its way down. Nearby, off CR2 toward Eureka, a slab cut out of the west face of Galena from about 12,500'. This slide was 2 feet deep - to the ground - and ran approximately 1000 feet vertical. It is worth noting that while we have a deeper than average snowpack in many areas, there are also plenty of places, as the Galena slide indicates, that are relatively shallow and weak, particularly on sunny aspects. These are the places that are most likely to run to the ground. On northerly terrain, observers are reporting no obvious or consistent shear planes within the snowpack, and a particularly solid mid-pack. Backcountry riders are reporting consistently good, settled powder on northerly aspects, especially below treeline where there has been little wind effect. Starting zones with solar aspects have become sun-affected over the past several days. An increasingly high sun angle - have you felt the change? - and generally warm ambient air have conspired to build crusts on the surface of east-south-west aspects. To add to the mix, relatively cool, clear nights have allowed near surface facets to form on most aspects as well, particularly on terrain near and above treeline. With the weather pattern turning back into a more unsettled snowy regime, now is the time to start thinking of the snow surface and how any incoming snow will bond to it on various aspects and elevations. If you head out into the backcountry today, remember the slides that ran recently near Silverton and evaluate the snowpack you travel through carefully. Avalanche Danger The avalanche danger in the Northern San Juan is MODERATE on all aspects and elevations. You may find reactive slabs on slopes 35 degrees and steeper, particularly on sunny aspects above treeline. [57]Please let us know if you see any avalanche activity or signs of instability. San Juan South ============== Current Keywords: MODERATE, avalanche danger, facets, orographics, settled, trough, windslabs, Mountain Weather and Avalanche Forecast for the Southern San Juan Mountain Zone Forecast Issued on 2/20/2008 3:56:23 PM Forecaster: Ann Mellick Weather Synopsis The first in a series of Pacific storms is moving into the state today. Cloud cover is increasing and snow showers have begun on the high peaks in the San Juans. Moisture will continue to spread north, with showers possible in all mountain areas by sundown. This system has a good moisture tap, drawing off the coast of Baja, but weak orographics and moderate lapse rates will keep accumulations on the light side. However, the favored San Juan could pick up a foot by Thursday night. Expect cooler, though mild temperatures and unusually light winds until the trough axis passes Thursday night. A brief break in the weather comes Friday morning before the next trough rolls in. An extended period of unsettled weather promises more mountain snow through early next week. Weather Wednesday Night Thursday Thursday Night Temperature(°F) 13-18 18-23 10-15 Wind Speed(mph) 10-20 10-20 10-20 Wind Direction SW variable NW->SW Sky Cover Overcast Overcast Mostly Cloudy Snow(in) 3-6 4-7 0-3 Snowpack Discussion The upper snowpack has settled and strengthened over the last days of mild weather and no fresh slides have been reported since the weekend. With a new round of storms coming in, our attention turns to the snow surface. Crusts have formed on sunny aspects and at lower elevations. Cooler, shadier slopes have developed pronounced layers of near surface facets. While neither of the layers poses a danger today, both act as potential weak interfaces for future snowfall. Take note of the location and distribution of them as this will be important information as the snow piles up. Expect changing conditions in the backcountry on Thursday. Light winds will mean fairly uniform distributions of new snow. With our increasingly deep snowpack, the upper layers continue to be the area of primary concern. Check the bond between upper snowpack layers before venturing onto exposed terrain. Avalanche Danger The avalanche danger in the Southern San Juan is MODERATE on all aspects and elevations. You may find reactive windslabs on slopes 35 degrees and steeper, particularly on south and easterly aspects above treeline. [57]Please let us know if you see any avalanche activity or signs of instability. Sangre de Christo ================= Current Keywords: avalanche danger, crusts, facets, orographics, trough, windslabs, Mountain Weather and Avalanche Forecast for the Sangre De Cristo Zone Forecast Issued on 2/20/2008 4:03:28 PM Forecaster: Ann Mellick Weather Synopsis The first in a series of Pacific storms is moving into the state today. Cloud cover is increasing and snow showers have begun on the high peaks in the San Juans. Moisture will continue to spread north, with showers possible in all mountain areas by sundown. This system has a good moisture tap, drawing off the coast of Baja, but weak orographics and moderate lapse rates will keep accumulations on the light side. However, the favored San Juan could pick up a foot by Thursday night. Expect cooler, though mild temperatures and unusually light winds until the trough axis passes Thursday night. A brief break in the weather comes Friday morning before the next trough rolls in. An extended period of unsettled weather promises more mountain snow through early next week. Weather Wednesday Night Thursday Thursday Night Temperature(°F) 15-20 18-23 13-18 Wind Speed(mph) 10-20 5-15 5-15 Wind Direction SW variable variable Sky Cover Overcast Mostly Cloudy Overcast Snow(in) 0-3 3-6 1-3 Snowpack Discussion Recent strong northwesterly winds moved available snow onto south and easterly faces. The snowpack has been getting pummeled with wind all winter, resulting in lots of windslabs in all exposed locations. Many of these windslabs sit on weak facets and may be reactive to the weight of a backcountry traveler. Recent warmer weather has created crusts at lower elevations and on southerly aspects. As we move back to a snowier, more unsettled regime, remember that new snow will not likely stick well to these recently formed slick crusts. Avoid steep terrain until you have checked it out thoroughly and use extra caution on steep slopes near and above treeline. Avalanche Danger We have insufficient information to make an avalanche danger rating for the Sangres at this time. Watch for windslabs on steep, open slopes. Please send observations from this or any other zone to [57]caic@qwest.net Sawatch ======= Current Keywords: LOW, MODERATE, avalanche danger, crowns, facets, orographics, settle, slab, slabs, trough, weak layers, windloaded, Mountain Weather and Avalanche Forecast for the Sawatch Range Zone Forecast Issued on 2/20/2008 4:07:13 PM Forecaster: Ann Mellick Weather Synopsis The first in a series of Pacific storms is moving into the state today. Cloud cover is increasing and snow showers have begun on the high peaks in the San Juans. Moisture will continue to spread north, with showers possible in all mountain areas by sundown. This system has a good moisture tap, drawing off the coast of Baja, but weak orographics and moderate lapse rates will keep accumulations on the light side. However, the favored San Juan could pick up a foot by Thursday night. Expect cooler, though mild temperatures and unusually light winds until the trough axis passes Thursday night. A brief break in the weather comes Friday morning before the next trough rolls in. An extended period of unsettled weather promises more mountain snow through early next week. Weather Wednesday Night Thursday Thursday Night Temperature(°F) 13-18 18-23 10-15 Wind Speed(mph) 10-20 5-15 10-20 Wind Direction SW variable NW->SW Sky Cover Overcast Overcast Mostly Cloudy Snow(in) 0-3 1-4 0-2 Snowpack Discussion Snowmobilers triggered two very deep slab avalanches were reported on east aspects on the Leadville side of Independence Pass on Tuesday. The reporting party claimed the crowns ranged from 10-30 feet, but it has not been confirmed. One rider was caught, though was not in the main flow and luckily walked away uninjured. These slides remind us that deep slabs remain a very real problem; particularly near and above treeline. It may take just the right trigger to release such a slide, but the resulting avalanche could be very large. Remember that the whole season's snowpack remains balanced on top of weak basal facets from early in the season. This is a tricky time because while we are not seeing many slides, the ones that are running are profound. Our snowpack remains complex, including stacks of both soft and hard slabs and a variety of weak layers. While the recent deep slabs certainly get our attention, our main avalanche concern lies in the upper snowpack where unstable slabs exist near the snow surface. Mild weather has helped settle the snowpack significantly, but the most recent wind event deposited fresh slabs on east, southeast and south facing slopes near and above treeline. This is the most likely place to trigger an avalanche at this time. Avalanche activity has become less frequent though weak interfaces persist, keeping human triggered slides possible on steep slopes on a variety of aspects. Continually poke at the upper layers to gather snowpack information before venturing onto steeper terrain. Avalanche Danger The avalanche danger for the Sawatch Zone is MODERATE on all aspects near and above treeline and LOW on all aspect below treeline. Human triggered avalanches are possible on steep, windloaded slopes, and have the potential to break deeply. [57]Please let us know if you see any avalanche activity or experienced signs of instability. Steamboat ========= Current Keywords: LOW, MODERATE, avalanche danger, consolidated, crossloaded, drifts, faceting, orographics, slabs, sluffs, trough, Mountain Weather and Avalanche Forecast for the Steamboat and Parks Range Zone Forecast Issued on 2/20/2008 3:13:44 PM Forecaster: Ann Mellick Weather Synopsis The first in a series of Pacific storms is moving into the state today. Cloud cover is increasing and snow showers have begun on the high peaks in the San Juans. Moisture will continue to spread north, with showers possible in all mountain areas by sundown. This system has a good moisture tap, drawing off the coast of Baja, but weak orographics and moderate lapse rates will keep accumulations on the light side. However, the favored San Juan could pick up a foot by Thursday night. Expect cooler, though mild temperatures and unusually light winds until the trough axis passes Thursday night. A brief break in the weather comes Friday morning before the next trough rolls in. An extended period of unsettled weather promises more mountain snow through early next week. Weather Wednesday Night Thursday Thursday Night Temperature(°F) 12-17 20-25 10-15 Wind Speed(mph) 5-15 5-15 5-15 Wind Direction SW->NW NNW NW->SW Sky Cover Overcast Overcast Mostly Cloudy Snow(in) 0-2 0-2 0-2 Snowpack Discussion Backcountry travelers in the Steamboat Zone triggered a few 8" to 10" deep soft slabs on south and southeast aspects near Buffalo Pass on Tuesday. These small pockets ran in steep terrain near 10,600'. A skier north of the Steamboat Lake Ranger station triggered a small slide on a northeast aspect below treeline on Tuesday as well. The older snowpack has consolidated under the recent mild temperatures, and is now fairly strong. Recent slides have been modest in size and limited to surface layers. Cold nighttime temperatures have kept the faceting process going near the surface, so look for loose snow sluffs on cooler slopes as surface layers lose cohesion. Also, watch for drifts and recently deposited slabs on exposed slopes. Observers note that southerly aspects are particularly "plump", but you will find crossloaded pockets on a variety of aspects. Check the bond within upper layers before committing to steeper terrain. Avalanche Danger The avalanche danger for the Steamboat Zone is MODERATE on northeast, east, southeast and south aspects near and above treeline. The danger is LOW on all aspects below treeline and on southwest, west, northwest and north aspects at all elevations. If you have any observations or data to share, please send them to [57]caic@qwest.net. Vail ==== Current Keywords: LOW, MODERATE, crowns, facets, orographics, settle, slab, slabs, trough, windloaded, Mountain Weather and Avalanche Forecast for the Vail and Summit County Zone Forecast Issued on 2/20/2008 3:49:18 PM Forecaster: Ann Mellick Weather Synopsis The first in a series of Pacific storms is moving into the state today. Cloud cover is increasing and snow showers have begun on the high peaks in the San Juans. Moisture will continue to spread north, with showers possible in all mountain areas by sundown. This system has a good moisture tap, drawing off the coast of Baja, but weak orographics and moderate lapse rates will keep accumulations on the light side. However, the favored San Juan could pick up a foot by Thursday night. Expect cooler, though mild temperatures and unusually light winds until the trough axis passes Thursday night. A brief break in the weather comes Friday morning before the next trough rolls in. An extended period of unsettled weather promises more mountain snow through early next week. Weather Wednesday Night Thursday Thursday Night Temperature(°F) 10-15 15-20 7-12 Wind Speed(mph) 5-15 5-15 10-20 Wind Direction W variable WNW Sky Cover Overcast Overcast Mostly Cloudy Snow(in) 1-3 1-4 0-2 Snowpack Discussion Things have quieted down with no new slides reported since the weekend. Since then, mild weather has allowed the snowpack to settle and strengthen. Northwest wind earlier in the week loaded easterly and southerly aspects near and above treeline. Use caution in these areas where slabs may still be reactive to the weight of a backcountry traveler. In addition to surface instabilities deep slab instabilities are still lurking. A skier triggered a 6-8' deep slab avalanche in Peru Creek last Saturday. It ran on a south aspect, almost 2,000 vertical feet and deposited several feet of snow over the trail at the bottom. Snowmobilers triggered two more deep slabs in the neighboring Sawatch zone near Independence Pass on Tuesday. The slides ran on easterly aspects above treeline with crowns ranging from 10-30 feet, leaving up to 50 feet of debris at the bottom of the slope!! Yikes! One rider was caught, though was not in the main flow and luckily walked away uninjured. These slides remind us that deep slabs remain a very real problem; particularly near and above treeline. It may take just the right trigger to release such a slide, but the resulting avalanche could be very large. Rember that the whole season's snowpack remains balanced on top of weak basal facets from early in the season. This is a tricky time because while we are not seeing many slides, the ones that are running are profound. Use caution in exposed, above treeline terrain and slowly work your way onto steeper slopes. Avalanche Danger The danger is MODERATE on all aspects near and above treeline and LOW on all aspects below treeline. Keep an eye on on steep, windloaded east, southeast, and south aspects near and above treeline. Human triggered avalanches are possible on steep, windloaded slopes, and have the potential to break deeply. [57]Please let us know if you see any avalanche activity or experienced signs of instability.