Aspen ===== Current Keywords: MODERATE, crusts, depth hoar, facets, human triggered avalanches, natural, orographics, settle, slab, slabs, surface hoar, weak layer, wind loaded, wind slab, wind slabs, windloading, Mountain Weather and Avalanche Forecast for the Aspen Zone Forecast Issued on 2/19/2008 3:19:37 PM Forecaster: Ann Mellick Weather Synopsis A dry and stable airmass has moved over the region. The state is under mostly clear skies, except for in the San Juan where some high clouds are streaming through. Expect mild temperatures and light winds, with increasing cloudiness on Wednesday as a weak closed low slides into the southern Colorado. Snow showers will begin in the San Juans by Wednesday afternoon, and spread north and east by the evening. Weak orographics and moderate lapse rates will keep accumulations on the modest side, except in the San Juan, where moisture is deepest. Snow showers and unsettled weather will continue through Thursday night, when a weak and short-lived ridge builds in. An active weather pattern promises more snow over the weekend. Weather Tuesday Night Wednesday Wednesday Night Temperature(°F) 15-20 22-27 15-20 Wind Speed(mph) 10-20 5-15 5-15 Wind Direction WSW WSW variable Sky Cover Partly Cloudy Mostly Cloudy Overcast Snow(in) 0 0-1 0-3 Snowpack Discussion Mild weather has helped to settle our snowpack, but we are still seeing the effects of recent strong winds. Northwest winds picked up Saturday afternoon and continued through Monday, loading available snow onto east, southeast and south aspects, adding another tender layer 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. If you are traveling near or above treeline today, watch out for these recently deposited wind slabs on slopes facing east, southeast, and south. In some areas these slabs will be resting on older slick sun crusts. Avalanches triggered on this layer could be fast movers and travel some distance down the slope. 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. While none of the layers on top of the snowpack are a concern for avalanche activity today, you will want to take note of there location as the next storm approaches. These may be our next weak layer of concern as the snow totals add up later this week. Although many areas of the zone have a deeper and stronger snowpack as a result of an above average snow year, there are still a few places where larger avalanches can be triggered. Above treeline, numerous wind events in the last couple weeks have left us with multiple layers of wind slab in the upper snowpack on a variety of aspects. In the right location, you may see avalanches stepping down through these slabs to become larger events. Also around Independence Pass, observers continue to mention the presence of a deep weak layer of facets and depth hoar at the base of the snowpack. Good snowpack observations during your day in the backcountry will help you sort out these variable conditions. 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: MODERATE, faceted, human triggered avalanches, orographics, settle, slab, slabs, wind loaded, windloaded, Mountain Weather and Avalanche Forecast for the Front Range Zone Forecast Issued on 2/19/2008 3:17:16 PM Forecaster: Ann Mellick Weather Synopsis A dry and stable airmass has moved over the region. The state is under mostly clear skies, except for in the San Juan where some high clouds are streaming through. Expect mild temperatures and light winds, with increasing cloudiness on Wednesday as a weak closed low slides into the southern Colorado. Snow showers will begin in the San Juans by Wednesday afternoon, and spread north and east by the evening. Weak orographics and moderate lapse rates will keep accumulations on the modest side, except in the San Juan, where moisture is deepest. Snow showers and unsettled weather will continue through Thursday night, when a weak and short-lived ridge builds in. An active weather pattern promises more snow over the weekend. Weather Tuesday Night Wednesday Wednesday Night Temperature(°F) 10-15 23-28 10-15 Wind Speed(mph) 10-20 10-20 5-15 Wind Direction W W variable Sky Cover Partly Cloudy Mostly Cloudy Mostly Cloudy Snow(in) 0 0 0-2 Snowpack Discussion The last reported avalanches in the Front Range ran over the weekend, most of the slides running on easterly aspects, some breaking up to 5 feet deep. Two main avalanche concerns still exist: instabilities near the surface and near the ground. As recent stability tests and triggered slides indicate, surface instabilities are easier to trigger, but deep slab instabilities are still lurking. We feel like a broken record saying this, but evidence of the weak nature of the deeply buried faceted grains, continues to rear its ugly head. It may take just the right trigger to release such a slide, but the resulting avalanche could be quite large. A skier triggered one such slide in Summit County last weekend. Luckily, no one was caught. Use caution in big, above treeline terrain and slowly work your way onto steeper slopes. Warmer temperatures have helped settle the middle of the snowpack, leaving some surface instabilities in recently deposited slabs. Northwest winds picked up Saturday afternoon and continued through Monday, loading available snow onto east, southeast and south aspects near and above treeline. Observers in the Cameron Pass area on Monday noted cracking and soft slab conditions on north facing slopes near treeline. Use caution in wind loaded areas and keep the consequence of a deep slab in the back of your mind. Avalanche Danger The danger in the Front Range Zone is MODERATE on all aspects and elevations. 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, whumpfing, wind loaded, Mountain Weather and Avalanche Forecast for the Grand Mesa Zone Forecast Issued on 2/19/2008 3:27:32 PM Forecaster: Ann Mellick Weather Synopsis A dry and stable airmass has moved over the region. The state is under mostly clear skies, except for in the San Juan where some high clouds are streaming through. Expect mild temperatures and light winds, with increasing cloudiness on Wednesday as a weak closed low slides into the southern Colorado. Snow showers will begin in the San Juans by Wednesday afternoon, and spread north and east by the evening. Weak orographics and moderate lapse rates will keep accumulations on the modest side, except in the San Juan, where moisture is deepest. Snow showers and unsettled weather will continue through Thursday night, when a weak and short-lived ridge builds in. An active weather pattern promises more snow over the weekend. Weather Tuesday Night Wednesday Wednesday Night Temperature(°F) 18-23 30-35 18-23 Wind Speed(mph) 0-10 0-10 0-10 Wind Direction SW SW variable Sky Cover Increasing Mostly Cloudy Mostly Cloudy Snow(in) 0 0-1 0-3 Snowpack Discussion Warm temperatures and light winds have encouraged rapid 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. 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, crust, crusts, entraining, facet, facets, orographics, powder , settled, shear, slab, windloaded, wind-loading, windslabs, Mountain Weather and Avalanche Forecast for the Northern San Juan Mountain Zone Forecast Issued on 2/19/2008 3:37:42 PM Forecaster: Ann Mellick Weather Synopsis A dry and stable airmass has moved over the region. The state is under mostly clear skies, except for in the San Juan where some high clouds are streaming through. Expect mild temperatures and light winds, with increasing cloudiness on Wednesday as a weak closed low slides into the southern Colorado. Snow showers will begin in the San Juans by Wednesday afternoon, and spread north and east by the evening. Weak orographics and moderate lapse rates will keep accumulations on the modest side, except in the San Juan, where moisture is deepest. Snow showers and unsettled weather will continue through Thursday night, when a weak and short-lived ridge builds in. An active weather pattern promises more snow over the weekend. Weather Tuesday Night Wednesday Wednesday Night Temperature(°F) 17-22 22-27 15-20 Wind Speed(mph) 10-20 5-15 5-15 Wind Direction SW SW variable Sky Cover Increasing Mostly Cloudy Overcast Snow(in) 0 0-2 2-5 Snowpack Discussion Slide activity has slowed again as the snowpack settled under recent mild weather. The last reported significant slab avalanche ran in Minnesota Gulch (previously reported as Fairview Gulch) up CR110 on Sunday. This hard slab started on a windloaded southeast aspect above treeline, and broke 6 to 8 feet deep to the ground, entraining lots of snow on its way down. Yikes! This slide is a bit of an anomaly, but a big warning sign nevertheless. Our main avalanche concern remains near the surface in our unusually deep snowpack, but remember that deep slab avalanches remain a possibility as well. Backcountry travelers are getting after the big lines again and so far, without incident. On northerly terrain, observers are reporting no obvious or consistent shear planes and a particularly solid mid-pack. Backcountry riders report good skiing on settled powder on the northerly aspects below treeline. Starting zones with east and southerly aspects continue to have the most problematic crust/facet combinations. These slopes have taken the bulk of the wind-loading from recent north-northwest winds as well, so use caution if traveling on these slopes at any point during a tour. With the weather pattern turning back into a more unsettled snowy regime, start thinking of the snow surface and how new snow will bond to it on various aspects and elevations. Recent mild weather allowed the snowpack to adjust to recent loads, but also created crusts on sunny and low elevations slopes and near surface facets on cooler, higher terrain. Neither will make a great foundation for significant new snow load. Continue to practice safe travel protocols while traveling in the backcountry today. With care, you can get into steeper terrain and bigger lines, but evaluate the snowpack very carefully. Avalanche Danger The avalanche danger in the Northern 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. San Juan South ============== Current Keywords: MODERATE, avalanche danger, faceting, orographics, settle, slabs, weak layer, windslabs, Mountain Weather and Avalanche Forecast for the Southern San Juan Mountain Zone Forecast Issued on 2/19/2008 3:38:31 PM Forecaster: Ann Mellick Weather Synopsis A dry and stable airmass has moved over the region. The state is under mostly clear skies, except for in the San Juan where some high clouds are streaming through. Expect mild temperatures and light winds, with increasing cloudiness on Wednesday as a weak closed low slides into the southern Colorado. Snow showers will begin in the San Juans by Wednesday afternoon, and spread north and east by the evening. Weak orographics and moderate lapse rates will keep accumulations on the modest side, except in the San Juan, where moisture is deepest. Snow showers and unsettled weather will continue through Thursday night, when a weak and short-lived ridge builds in. An active weather pattern promises more snow over the weekend. Weather Tuesday Night Wednesday Wednesday Night Temperature(°F) 18-23 23-28 15-20 Wind Speed(mph) 10-20 10-20 5-15 Wind Direction WSW SW SW Sky Cover Increasing Mostly Cloudy Overcast Snow(in) 0 0-2 3-6 Snowpack Discussion Mild weather both before and after last week's storm helped the snowpack to settle and strengthen. The most recent slides ran over the weekend on easterly aspects. Two broke in the upper 2 feet of the snowpack while the third broke three feet deep to the ground. The upper snowpack continues to be the area of primary concern in our increasingly deep snowpack. With care, you can get into steeper terrain and bigger lines, but evaluate the snowpack very carefully. Expect to find slabs on steep, high elevation east, southeast, south and southwest aspects near and above treeline from recent strong northerly winds. Check the bond between upper snowpack layers before venturing onto big exposed terrain. Warm temperatures have baked lower elevations, especially sunny ones, while near surface faceting has prevailed on cooler aspects. Remember, today's surface snow may serve as our next weak layer when the next storm rolls in. Wednesday's slightly cooler temperatures and cloud cover will slow wet activity, but watch for surface wet instabilities on southerly slopes if temperatures exceed expectations. 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, windslabs, Mountain Weather and Avalanche Forecast for the Sangre De Cristo Zone Forecast Issued on 2/19/2008 3:41:43 PM Forecaster: Ann Mellick Weather Synopsis A dry and stable airmass has moved over the region. The state is under mostly clear skies, except for in the San Juan where some high clouds are streaming through. Expect mild temperatures and light winds, with increasing cloudiness on Wednesday as a weak closed low slides into the southern Colorado. Snow showers will begin in the San Juans by Wednesday afternoon, and spread north and east by the evening. Weak orographics and moderate lapse rates will keep accumulations on the modest side, except in the San Juan, where moisture is deepest. Snow showers and unsettled weather will continue through Thursday night, when a weak and short-lived ridge builds in. An active weather pattern promises more snow over the weekend. Weather Tuesday Night Wednesday Wednesday Night Temperature(°F) 17-22 23-28 15-20 Wind Speed(mph) 10-20 10-20 10-20 Wind Direction W WSW SW Sky Cover Increasing Mostly Cloudy Mostly Cloudy Snow(in) 0 0 0-2 Snowpack Discussion An observer near the Sangres noted that the range received a good bit of snow last weekend. 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, faceted, human triggered, natural, orographics, settle, slabs, weak layers, windloaded, windslabs, Mountain Weather and Avalanche Forecast for the Sawatch Range Zone Forecast Issued on 2/19/2008 4:08:14 PM Forecaster: Ann Mellick Weather Synopsis A dry and stable airmass has moved over the region. The state is under mostly clear skies, except for in the San Juan where some high clouds are streaming through. Expect mild temperatures and light winds, with increasing cloudiness on Wednesday as a weak closed low slides into the southern Colorado. Snow showers will begin in the San Juans by Wednesday afternoon, and spread north and east by the evening. Weak orographics and moderate lapse rates will keep accumulations on the modest side, except in the San Juan, where moisture is deepest. Snow showers and unsettled weather will continue through Thursday night, when a weak and short-lived ridge builds in. An active weather pattern promises more snow over the weekend. Weather Tuesday Night Wednesday Wednesday Night Temperature(°F) 15-20 22-27 15-20 Wind Speed(mph) 10-20 5-15 5-15 Wind Direction W WSW variable Sky Cover Increasing Mostly Cloudy Mostly Cloudy Snow(in) 0 0-1 0-3 Snowpack Discussion The recent mild weather helped settle the snowpack significantly. Avalanche activity has become less frequent though weak interfaces persist, keeping human triggered slides possible on steep slopes on a variety of aspects. More natural activity was observed over the weekend in the far northern portion of the zone. Three small slabs ran on east and south aspects near and above treeline. Our snowpack is complex, including stacks of both soft and hard slabs and a variety of weak layers. Look for unstable slabs near the snowpack surface. Shallow accumulations and winds from a variety of directions have formed windslabs on many slopes in the alpine zone. The most recent wind event deposited fresh slabs on east, southeast and south aspects near and above treeline. This is the most likely place to trigger an avalanche at this time. Continually poke at the upper layers to gather snowpack information before venturing onto steeper terrain. Deep slabs remain an infrequent but very real problem; particularly near and above treeline. We feel like a broken record saying this, but evidence of the weak nature of the deeply buried faceted grains, continues to rear its ugly head. It may take just the right trigger to release such a slide, but the resulting avalanche could be quite large. Deep slabs are tricky to predict so use caution and work into steeper terrain slowly. 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, crossloading, drifting, drifts, human triggered avalanches, orographics, slabs, sluff, windslabs, Mountain Weather and Avalanche Forecast for the Steamboat and Parks Range Zone Forecast Issued on 2/19/2008 3:14:53 PM Forecaster: Ann Mellick Weather Synopsis A dry and stable airmass has moved over the region. The state is under mostly clear skies, except for in the San Juan where some high clouds are streaming through. Expect mild temperatures and light winds, with increasing cloudiness on Wednesday as a weak closed low slides into the southern Colorado. Snow showers will begin in the San Juans by Wednesday afternoon, and spread north and east by the evening. Weak orographics and moderate lapse rates will keep accumulations on the modest side, except in the San Juan, where moisture is deepest. Snow showers and unsettled weather will continue through Thursday night, when a weak and short-lived ridge builds in. An active weather pattern promises more snow over the weekend. Weather Tuesday Night Wednesday Wednesday Night Temperature(°F) 10-15 27-32 10-15 Wind Speed(mph) 5-15 5-15 5-15 Wind Direction WSW WSW variable Sky Cover Partly Cloudy Increasing Mostly Cloudy Snow(in) 0 0-1 0-2 Snowpack Discussion Observers in Steamboat Zone reported a few surface slides on Sand Mt. and Saddle Mt. early this week. Otherwise, things have been quiet. The older snowpack has consolidated under the recent mild temperatures, and is now fairly strong. Northwesterly winds over the weekend blew at an ideal speed for drifting snow, so watch for fresh windslabs at higher elevations and on exposed slopes. Most of the slabs will be on east to south aspects, but you will find some crossloading most aspects. Those fresh drifts and windslabs are the main avalanche concern. Check the bond within upper layers before committing to steeper terrain. New snow may not stick well to older, harder surfaces and even a relatively small sluff may take you somewhere you do not want to be. With the problem near the surface, there is no excuse for not digging around. Avalanche Danger The avalanche danger for the Steamboat Zone is MODERATE on all aspects above treeline and on north, northeast, east, southeast and south aspects near treeline. Human triggered avalanches are possible on all aspects near and above treeline. Watch for recent drifting and loading. The danger is LOW on all aspects below treeline and on southwest, west and northwest aspects near treeline. If you have any observations or data to share, please send them to [57]caic@qwest.net. Vail ==== Current Keywords: MODERATE, human triggered avalanches, orographics, settle, slab, slabs, weak layers, windloaded, windloading, windslabs, Mountain Weather and Avalanche Forecast for the Vail and Summit County Zone Forecast Issued on 2/19/2008 3:18:49 PM Forecaster: Ann Mellick Weather Synopsis A dry and stable airmass has moved over the region. The state is under mostly clear skies, except for in the San Juan where some high clouds are streaming through. Expect mild temperatures and light winds, with increasing cloudiness on Wednesday as a weak closed low slides into the southern Colorado. Snow showers will begin in the San Juans by Wednesday afternoon, and spread north and east by the evening. Weak orographics and moderate lapse rates will keep accumulations on the modest side, except in the San Juan, where moisture is deepest. Snow showers and unsettled weather will continue through Thursday night, when a weak and short-lived ridge builds in. An active weather pattern promises more snow over the weekend. Weather Tuesday Night Wednesday Wednesday Night Temperature(°F) 10-15 22-27 10-15 Wind Speed(mph) 10-20 10-20 5-15 Wind Direction SW WSW variable Sky Cover Partly Cloudy Mostly Cloudy Mostly Cloudy Snow(in) 0 0-1 0-2 Snowpack Discussion Things have quieted down with no new slides reported since the weekend, when observers noted easily triggered soft slabs below ridgelines, especially on easterly aspects. Since then, mild weather has allowed the snowpack to settle a bit. Strong northwest winds blew from Saturday until Monday so expect to find windslabs loaded onto easterly and southerly aspects near and above treeline. Use caution in these areas where fresh slabs may still be reactive to the weight of a backcountry traveler. In addition to surface instabilities, yes, deep slab instabilities are still lurking. A skier triggered a deep slab avalanche in Peru Creek last Saturday. It broke 6-8 feet deep, ran almost full track, and deposited several feet of snow over the trail at the bottom. It ran on a south aspect, over 1,800 vertical feet. While triggering such a deep slide may not be that likely, it certainly remains possible, so use caution in big, above treeline terrain and slowly work your way onto steeper slopes. The most likely place to trigger a deep slab is on convexities, near rock bands, vegetation, or low on the slope where slabs are thinner and weak layers are closer to the surface. Continue to practice smart travel procedures and sound decision making while traveling in the backcountry today. Avalanche Danger The danger is MODERATE on all aspects and elevations. Keep an eye on on windloaded east, southeast, and south aspects near and above treeline. Watch slopes steeper than 35 degrees with fresh windloading. 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.