Aspen ===== Current Keywords: CONSIDERABLE, MODERATE, avalanche danger, collapsing , drift, facets, human triggered, settled, slabs, trough, windloading, Mountain Weather and Avalanche Forecast for the Aspen Zone Forecast Issued on 12/11/2007 3:59:40 PM Forecaster: Spencer Logan Weather Synopsis It may not feel like it, but we are on the tapering end of the storm. Wolf Creek Pass was the big winner with this storm. As of noon Tuesday, the storm total was 29 inches and snow was still falling. There is enough moisture in the airmass overhead to keep light snow going overnight, and scattered snow around tomorrow. Winds will swing to the west overnight, but wind speeds will not really pick up. The trough axis will track eastward overnight. As it does, upper level flow will turn westerly. Short waves will keep the weather unsettled with a chance of snow until Thursday night, when it looks like another strong system arrives. Weather Tuesday Night Wednesday Wednesday Night Temperature(°F) 0-5 10-15 0-5 Wind Speed(mph) 10-20 15-25 15-25 Wind Direction WSW W NW Sky Cover Mostly Cloudy Mostly Cloudy Partly Cloudy Snow(in) 2-5 0-1 Tr Snowpack Discussion Recent lack of results from avalanche mitigation work at a local ski area indicates that last week's storm snow has settled well. Signs of instability have been minimal on southerly aspects. On westerly, northerly, and easterly aspects, we continue to receive reports of collapsing and cracking, but avalanche activity has diminished. Avalanche conditions will continue to be a bit tricky. Wind slabs and a weak base layer of cohesionless facets still exist on steep west, northwest, north, northeast, and east aspects near and above treeline. Human triggered slides are still probable. Do not let your guard down. The little bit of new snow will increase the instability, especially on those problematic northerly facing aspects. It will drift onto northwest, north, and northeast aspects. Always watch for signs of instability such as cracking and collapsing, and choose your terrian accordingly. Riding conditions are excellent, but you will need to temper powder fever with careful route finding and terrain management. Terrain choices are very important. Watch your slope angles carefully, and avoid traveling on or below slopes steeper than 30 degrees on the problematic northerly aspects. Do not ignore the signs of instability. It's a great time to use your clinometers and compasses. Avalanche Danger The avalanche danger in the Aspen Zone is CONSIDERABLE on west, northwest, north, northeast, and east aspects near and above treeline. There is new windloading on the top of the snowpack and weak, old facets on the bottom. Elsewhere the danger is MODERATE. Your backcountry observations are VERY important to us. Observations can be sent to [58]caic@qwest.net. Front Range =========== Current Keywords: CONSIDERABLE, MODERATE, avalanche danger, collapses, collapsing,, drifted, facets, natural, snow pit, trough, whumpf, wind loaded, windloaded, windslab, Mountain Weather and Avalanche Forecast for the Front Range Zone Forecast Issued on 12/11/2007 3:16:09 PM Forecaster: Spencer Logan Weather Synopsis It may not feel like it, but we are on the tapering end of the storm. Wolf Creek Pass was the big winner with this storm. As of noon Tuesday, the storm total was 29 inches and snow was still falling. There is enough moisture in the airmass overhead to keep light snow going overnight, and scattered snow around tomorrow. Winds will swing to the west overnight, but wind speeds will not really pick up. The trough axis will track eastward overnight. As it does, upper level flow will turn westerly. Short waves will keep the weather unsettled with a chance of snow until Thursday night, when it looks like another strong system arrives. Weather Tuesday Night Wednesday Wednesday Night Temperature(°F) 0-5 10-15 Wind Speed(mph) 15-25 20-30 Wind Direction SW W Sky Cover Mostly Cloudy Mostly Cloudy Overcast Snow(in) 0-2 0-1 Snowpack Discussion The Front Range snowpack remains tricky. Observers (and myself) are using words like "spooky" and "angry" to describe the snowpack. There are plenty of sings of instability, from recent avalanches, massive collapses, shooting cracks, to weak facets that pour out of snow pit walls. Observers continue to report "widespread" cracking and collapsing, "though nothing like the weekend." Monday, my partner and I remotely triggered an avalanche from 200 feet away. We were on low-angled, north facing terrain below treeline. A massive whumpf spread out several hundred feet, and initiated a 3 foot deep avalanche on steep slopes below us. Most avalanche activity has occurred on northwest, north, northeast and east aspects, where there is old, weak snow at the bottom of the snowpack. The majority of the natural activity has been near and above treeline in windloaded areas. People have triggered avalanches at all elevations, and below treeline slopes may be the most problematic for human triggering. The few inches of new snow overnight and today will be drifted onto the weak northerly aspects. Expect to find a new layer of soft windslab above treeline. Where snowfall was not on the ground prior to last weekend's storm the snowpack stability is good. That is generally on southeast, south, southwest and west aspects. Without That old, weak snow the signs of instability have been minimal. Riding conditions are excellent, but you will need to temper powder fever with careful route finding and terrain management. Terrain choices are very important. Watch your slope angles carefully, and avoid traveling on or below slopes steeper than 30 degrees on the problematic aspects. It's a great time to use your clinometers and compasses. Avalanche Danger The avalanche danger for the Front Range zone is CONSIDERABLE on northwest, north, northeast, and east aspects at all elevations. Human triggered avalanches are probable on steep slopes that have a weak base layer or are wind loaded. Elsewhere, the avalanche danger is MODERATE. Grand Mesa ========== Current Keywords: MODERATE, avalanche danger, settled, slabs, sluffing, trough, Mountain Weather and Avalanche Forecast for the Grand Mesa Zone Forecast Issued on 12/11/2007 2:55:01 PM Forecaster: Spencer Logan Weather Synopsis It may not feel like it, but we are on the tapering end of the storm. Wolf Creek Pass was the big winner with this storm. As of noon Tuesday, the storm total was 29 inches and snow was still falling. There is enough moisture in the airmass overhead to keep light snow going overnight, and scattered snow around tomorrow. Winds will swing to the west overnight, but wind speeds will not really pick up. The trough axis will track eastward overnight. As it does, upper level flow will turn westerly. Short waves will keep the weather unsettled with a chance of snow until Thursday night, when it looks like another strong system arrives. Weather Tuesday Night Wednesday Wednesday Night Temperature(°F) 12-17 15-20 12-18 Wind Speed(mph) 0-10 0-10 0-10 Wind Direction SW WSW W Sky Cover Mostly Cloudy Mostly Cloudy Partly Cloudy Snow(in) 0-2 0-1 Tr Snowpack Discussion Natural avalanche activity was reported across the Grand Mesa on Friday, some of the avalanches bringing down quite a bit of snow. All of the reported activity came from steep north aspect terrain. The weekend snow fell with warm temperatures and settled well. A few inches of new snow are sitting on top. This makes a pretty good snowpack--weak over strong snow. Expect some sluffing off very steep slopes. You may find a few pockets where there is old, very weak snow underneath. These will be problematic, and you can trigger avalanches fairly easy in these pockets. Watch out for these exceptions to the generally stable snowpack. Avalanche Danger The avalanche danger for the Grand Mesa zone is MODERATE. Unstable slabs are possible on steep north facing slopes where there is old, weak snow at the base of the snowpack. Your backcountry observations are VERY important to us. Observations can be submitted to [58]caic@qwest.net. San Juan North ============== Current Keywords: CONSIDERABLE, HIGH, avalanche danger, cross-loading, dense, drifts, faceted, facets, natural, paths, powder , slab, slabs, suncrusts, trough, Mountain Weather and Avalanche Forecast for the Northern San Juan Mountain Zone Forecast Issued on 12/11/2007 6:54:44 AM Forecaster: Spencer Logan Weather Synopsis It may not feel like it, but we are on the tapering end of the storm. Wolf Creek Pass was the big winner with this storm. As of noon Tuesday, the storm total was 29 inches and snow was still falling. There is enough moisture in the airmass overhead to keep light snow going overnight, and scattered snow around tomorrow. Winds will swing to the west overnight, but wind speeds will not really pick up. The trough axis will track eastward overnight. As it does, upper level flow will turn westerly. Short waves will keep the weather unsettled with a chance of snow until Thursday night, when it looks like another strong system arrives. Weather Tuesday Tuesday Night Wednesday Temperature(°F) 15-20 0-5 10-15 Wind Speed(mph) 15-25 10-20 15-25 Wind Direction S SW W Sky Cover Overcast Mostly Cloudy Mostly Cloudy Snow(in) 4-7 1-3 0-1 Snowpack Discussion Reports of natural and triggered avalanche activity continue to come in. Dozens of slides have been reported, particularly from the Ophir and Telluride area. Most, but not all, of these slides occurred on northerly aspects near and above treeline and some of the details are impressive. Both hard and soft slabs have been observed, with fracture lines ranging up to 8-feet deep! Last week's storm snow was dense and quickly formed very cohesive slabs. This cohesiveness creates the potential for extensive propagation in slab avalanche releases. Observations of natural and triggered avalanches confirmed this, with reports of several wide fracture lines spanning distances up to 500 feet. New snow now tops the slabs, with more to come today. This will make for excellent riding conditions. But, and it's a big BUT, there are instabilities in the snowpack to deal with. Temper your powder lust with a healthy dose of caution. The areas that have been most active and continue to be of particular concern are northerly (NW-N-NE) aspects at all elevations. These slopes have a combination of new drifts and loading, heavy slabs from the last two storms, all sitting above relatively weak, faceted snow grains at their base. East and west aspects developed suncrusts and associated near-surface facets and relatively fresh slabs are testing that interface. Southerly aspects still have relatively little snow in them but high winds caused cross-loading on certain southerly paths during the recent storm and caused some significant releases, particularly in the Red Mt. Pass area. We have a complicated snowpack that requires respect and continual evaluation as you tour in the backcountry - have fun out there, but be careful. Please attend the CAIC Fundraiser in Telluride this Wednesday, Dec 12, at the Cornerhouse Grille, downtown Telluride. A raffle and silent auction on local business items will be held from 6-8 pm. Avalanche Danger The avalanche danger is HIGH on NW-N-NE aspects at all elevations. On E and W aspects, the danger is CONSIDERABLE all elevations. On SE-S-SW San Juan South ============== Current Keywords: CONSIDERABLE, HIGH, avalanche danger, human triggered avalanches, paths, powder , slabs, trough, Mountain Weather and Avalanche Forecast for the Southern San Juan Mountain Zone Forecast Issued on 12/11/2007 6:46:07 AM Forecaster: Spencer Logan Weather Synopsis It may not feel like it, but we are on the tapering end of the storm. Wolf Creek Pass was the big winner with this storm. As of noon Tuesday, the storm total was 29 inches and snow was still falling. There is enough moisture in the airmass overhead to keep light snow going overnight, and scattered snow around tomorrow. Winds will swing to the west overnight, but wind speeds will not really pick up. The trough axis will track eastward overnight. As it does, upper level flow will turn westerly. Short waves will keep the weather unsettled with a chance of snow until Thursday night, when it looks like another strong system arrives. Weather Tuesday Tuesday Night Wednesday Temperature(°F) 20-25 5-10 15-20 Wind Speed(mph) 10-20 10-20 10-20 Wind Direction S SSW SW Sky Cover Overcast Mostly Cloudy Mostly Cloudy Snow(in) 8-12 1-4 0-2 Snowpack Discussion Another storm! As of 5 am, the storm total on Wolf Creek Pass was 22 inches, with 14 inches falling overnight. Storm totals are not as deep along the southern 550 corridor, probably closer to a foot. Another foot of snow could fall today. Powder anyone? Of course, the new load means a touchy snowpack. Overnight, many road cuts along Highway 160 avalanched. The slabs were only about a foot deep, but propagating far. At upper elevation winds were from the south and southeast, loading northerly aspects. All indications continue to point toward an unstable snowpack. Human triggered avalanches will be probable to likely on many steep slopes in the backcountry. Watch the slopes that are above you, and stay out from underneath steep slopes and avalanche paths. Temper your powder fever with careful route finding and terrain management. Avalanche Danger Tha avalanche danger is HIGH on west, northwest, north, northeast, east, and southeast aspects at all elevations. The danger is CONSIDERABLE on other aspects. Sangre de Christo ================= Current Keywords: avalanche danger, collapsing,, drifted, drifts, trough, whumpfing, wind slabs, Mountain Weather and Avalanche Forecast for the Sangre De Cristo Zone Forecast Issued on 12/11/2007 2:34:45 PM Forecaster: Spencer Logan Weather Synopsis It may not feel like it, but we are on the tapering end of the storm. Wolf Creek Pass was the big winner with this storm. As of noon Tuesday, the storm total was 29 inches and snow was still falling. There is enough moisture in the airmass overhead to keep light snow going overnight, and scattered snow around tomorrow. Winds will swing to the west overnight, but wind speeds will not really pick up. The trough axis will track eastward overnight. As it does, upper level flow will turn westerly. Short waves will keep the weather unsettled with a chance of snow until Thursday night, when it looks like another strong system arrives. Weather Tuesday Night Wednesday Wednesday Night Temperature(°F) 5-10 15-20 10-15 Wind Speed(mph) 10-20 15-25 15-25 Wind Direction W WNW WNW Sky Cover Mostly Cloudy Mostly Cloudy Partly Cloudy Snow(in) 0-2 0-2 0 Snowpack Discussion The Ute Creek SNOTEL site shows 9 inches of snow of snow so far. Temperatures have been nice and cold, meaning the snow is light and fluffy. It will be easily transported, drifted, and loaded by the winds. Watch for new, soft drifts, and check out the older snow underneath. How well the new snow bonds will depend a lot on that old snow surface. Around the state the most problematic areas are spots that have very weak, old snow at the ground. The weak snow makes a poor foundation, with all the overlying snow cracking, collapsing, and avalanching. Watchful for signs of instability such as cracking, whumpfing, and recent avalanche activity. Keep your guard up on north, northeast, and east aspects where wind slabs and a weak base layer may exist. Avalanche Danger We have insufficient data to rate the avalanche danger in the Sangre de Cristo Zone. Please send observations from this or any other zone to [58]caic@qwest.net Sawatch ======= Current Keywords: CONSIDERABLE, MODERATE, avalanche danger, drift, faceted, run out zones, slabby, slabs, trough, wind loaded, windloading, Mountain Weather and Avalanche Forecast for the Sawatch Range Zone Forecast Issued on 12/11/2007 3:40:33 PM Forecaster: Spencer Logan Weather Synopsis It may not feel like it, but we are on the tapering end of the storm. Wolf Creek Pass was the big winner with this storm. As of noon Tuesday, the storm total was 29 inches and snow was still falling. There is enough moisture in the airmass overhead to keep light snow going overnight, and scattered snow around tomorrow. Winds will swing to the west overnight, but wind speeds will not really pick up. The trough axis will track eastward overnight. As it does, upper level flow will turn westerly. Short waves will keep the weather unsettled with a chance of snow until Thursday night, when it looks like another strong system arrives. Weather Tuesday Night Wednesday Wednesday Night Temperature(°F) 3-8 15-20 0-5 Wind Speed(mph) 10-20 15-25 15-25 Wind Direction W WNW WNW Sky Cover Mostly Cloudy Mostly Cloudy Partly Cloudy Snow(in) 1-3 0-1 Tr Snowpack Discussion Totals from the most recent storm range from 5" to 10". The new snow will bond to the older snow from last week with varying results. The bond will be poor on wind loaded or slabby surfaces. These areas can be found near and above treeline on northeast, east, and southeast aspects. The loading will increase as winds pick up. The 5 to 10 inches of snow can drift into slabs several feet thick. The older snow underneath is generally stable. It came in wet and warm (for snow), creating a nice base for the colder, lighter snow that followed. The snowpack is not totally green light, jump into anything. There is the new snow slabs, and at the very bottom, pockets of old, weak faceted snow. The pockets will be hard to spot, so work into terrain carefully. Terrain choice and route finding will be key for the next few days. Be mindful of where you are and approach all slopes steeper than 30 degrees with caution. Avoid avalanche run out zones, ride one at a time and have escape routes planned. Avalanche Danger The avalanche danger is MODERATE with pockets of CONSIDERABLE on northwest, north, northeast, and east aspects near and above treeline. Watch for areas with fresh windloading, or that have old, weak snow at the ground. Steamboat ========= Current Keywords: MODERATE, avalanche danger, collapsing , explosive, facets, natural, settle, slabs, trough, Mountain Weather and Avalanche Forecast for the Steamboat and Parks Range Zone Forecast Issued on 12/11/2007 2:44:20 PM Forecaster: Spencer Logan Weather Synopsis It may not feel like it, but we are on the tapering end of the storm. Wolf Creek Pass was the big winner with this storm. As of noon Tuesday, the storm total was 29 inches and snow was still falling. There is enough moisture in the airmass overhead to keep light snow going overnight, and scattered snow around tomorrow. Winds will swing to the west overnight, but wind speeds will not really pick up. The trough axis will track eastward overnight. As it does, upper level flow will turn westerly. Short waves will keep the weather unsettled with a chance of snow until Thursday night, when it looks like another strong system arrives. Weather Tuesday Night Wednesday Wednesday Night Temperature(°F) 0-5 10-15 0-5 Wind Speed(mph) 5-15 10-20 15-25 Wind Direction SW W W Sky Cover Mostly Cloudy Mostly Cloudy Partly Cloudy Snow(in) 0-2 0-2 0-2 Snowpack Discussion Storm snow over the past week has not been as great as other parts of the state. A few inches fell Tuesday, making about a foot of snow since Friday. Mild post-storm temperatures helped to settle the snowpack. On Sunday an observer near Buffalo Pass noted a lot collapsing but not much cracking. In neighboring zones, natural avalanche activity has slowed, but we continue to get reports of human and explosive triggered slides. These are mostly coming from high elevation north, northeast, and east aspects. The problem slopes have wind affected snow and a weak base of cohesionless facets. Southerly and westerly aspects tend to not have the weak base layer and just have less snow. Watch for signs of instability, such as collapsing and cracking, on steep northerly to easterly aspects. Human triggered avalanches remain possible on these slopes. The signs are good indications to avoid traveling on or below steep slopes. The old, weak snow was patchy prior to the last couple storms. You can move from relatively stable snow, lacking the facets, to very weak facets over a short distance. Re-evaluate the snowpcak often, and do not get complacent. Avalanche Danger The avalanche danger in the Steamboat Zone is MODERATE. The most problematic areas are steep north, northeast, and east facing slopes that have old, weak snow underneath. Unstable slabs are possible on those slopes. If you have any observations to share, please send them to [58]caic@qwest.net. Vail ==== Current Keywords: CONSIDERABLE, MODERATE, avalanche danger, collapses, drifted, faceted, human triggered, human triggered avalanches, natural, powder , shear, trough, whumpfing, wind loaded, windloaded, windslab, Mountain Weather and Avalanche Forecast for the Vail and Summit County Zone Forecast Issued on 12/11/2007 3:29:12 PM Forecaster: Spencer Logan Weather Synopsis It may not feel like it, but we are on the tapering end of the storm. Wolf Creek Pass was the big winner with this storm. As of noon Tuesday, the storm total was 29 inches and snow was still falling. There is enough moisture in the airmass overhead to keep light snow going overnight, and scattered snow around tomorrow. Winds will swing to the west overnight, but wind speeds will not really pick up. The trough axis will track eastward overnight. As it does, upper level flow will turn westerly. Short waves will keep the weather unsettled with a chance of snow until Thursday night, when it looks like another strong system arrives. Weather Tuesday Night Wednesday Wednesday Night Temperature(°F) 0-5 10-15 0-5 Wind Speed(mph) 10-20 15-25 15-25 Wind Direction SW W W Sky Cover Mostly Cloudy Mostly Cloudy Partly Cloudy Snow(in) 0-2 0-1 0 Snowpack Discussion Signs of instability have been reported from locations throughout the zone. Tuesday near Francie's Cabin above Breckenridge, an observer reported widespread collapses and cracking, "though nothing like the weekend." Avalanches, both natural and human triggered have been reported as well. Most avalanche activity has occurred on northwest, north, northeast and east aspects, where there is old, weak snow at the bottom of the snowpack. The majority of the natural activity has been near and above treeline in windloaded areas. People have triggered avalanches at all elevations. The few inches of new snow overnight and today will be drifted onto the weak northerly aspects. Expect to find a new layer of soft windslab above treeline. Where snowfall was not on the ground prior to last weekend's storm the snowpack stability is good. That is generally on southeast, south, southwest and west aspects. Riding conditions are excellent, but you will need to temper powder fever with careful route finding and terrain management. Dig under the powder and you will find weakness. Faceted, sugar-like snow shows it's weakness by whumpfing. Whumpfing, large or small, can turn into a shear failure on any slope steep enough to slide. Terrain choices are very important. Watch your slope angles carefully, and avoid traveling on or below slopes steeper than 30 degrees on the problematic aspects. It's a great time to use your clinometers and compasses. Avalanche Danger The avalanche danger for the Vail Summit Zone is CONSIDERABLE on northwest, north, northeast, and east aspects near and above treeline. Human triggered avalanches are probable on steep slopes that have a weak base layer or are wind loaded. Elsewhere, the avalanche danger is MODERATE.