Aspen ===== Current Keywords: CONSIDERABLE, MODERATE, avalanche danger, drifted, facets, human triggered avalanches, natural, settles, slabs, trough, whumpfing, wind loaded, wind slabs, Mountain Weather and Avalanche Forecast for the Aspen Zone Forecast Issued on 12/5/2007 6:17:54 AM Forecaster: John Snook Weather Synopsis Moist flow, with embedded impulses, is setting up for an extended period of mountain snow. The first impulse is expected to arrive late tonight in west-northwest flow that favors the northern and central mountains where snowfall amounts in the 8-12" range are possible by Thursday afternoon. Snowfall is expected to continue through Friday with periods of heavier snow, the timing of which is difficult to define, but the snow will add up by this weekend. Upper-level flow slowly shifts to southwest by Friday as a deep trough digs in over the Great Basin. This will shift the focus of heaviest snow to the southwest mountains. Weather Wednesday Night Thursday Thursday Night Temperature(°F) 30-35 18-23 23-28 Wind Speed(mph) 10-20 15-25 G35 15-25 G35 Wind Direction W WSW W Sky Cover Increasing Overcast Overcast Snow(in) 0 4-6 4-6 Snowpack Discussion Recent mild temperatures have slowed natural slide activity as the snowpack settles. Strong winds, however, above treeline have continued during the past 24 hours. The continued loading of a weak snowpack remains a problem. In neighboring zones, we continue to receive reports of natural slide activity from isolated areas where large wind slabs have built - primarily steep slopes near and above treeline with NW-NE-SE aspects. These locations continue to be the area of greatest concern, especially where the wind slabs are perched atop rotten facets. Beware of drifted and loaded slopes, especially on NW-NE-SE aspects at higher elevations. Human triggered avalanches remain probable in these areas. Watch for signs of instability such as cracking, whumpfing, and recent avalanche activity. As the slabs strengthen, avalanches can propagate further and run larger. Consider the consequences of a bad decision before committing to steep slopes. New snow in the forecast will likely cause the avalanche danger to trend upward by Thursday. Forecaster Brian McCall will present an avalanche awareness talk on Wednesday, December 5. The event will run from 6:30-8 p.m. in the Rio Grande Commons. Space for the free avalanche awareness talk is limited, so if you plan to attend please RSVP to [59]info@PowderToThePeople.org, or call 970-920-3890. Avalanche Danger The avalanche danger in the Aspen Zone is CONSIDERABLE on NW-N-NE-E aspects near and above treeline. Human triggered avalanches remain probable on steep heavily wind loaded slopes. On other aspects and below treeline the danger is MODERATE. Your backcountry observations are very important to us. Observations can be submitted to [60]caic@qwest.net . Front Range =========== Current Keywords: CONSIDERABLE, MODERATE, avalanche danger, crowns, drifted, facets, human triggered avalanches, natural, settle, slabs, trough, whumpfing, wind loaded, wind slabs, Mountain Weather and Avalanche Forecast for the Front Range Zone Forecast Issued on 12/5/2007 6:16:26 AM Forecaster: John Snook Weather Synopsis Moist flow, with embedded impulses, is setting up for an extended period of mountain snow. The first impulse is expected to arrive late tonight in west-northwest flow that favors the northern and central mountains where snowfall amounts in the 8-12" range are possible by Thursday afternoon. Snowfall is expected to continue through Friday with periods of heavier snow, the timing of which is difficult to define, but the snow will add up by this weekend. Upper-level flow slowly shifts to southwest by Friday as a deep trough digs in over the Great Basin. This will shift the focus of heaviest snow to the southwest mountains. Weather Wednesday Night Thursday Thursday Night Temperature(°F) 28-33 18-23 23-28 Wind Speed(mph) 15-25 G35 15-25 G40 15-25 G40 Wind Direction W W W Sky Cover Increasing Overcast Overcast Snow(in) 0 4-6 4-6 Snowpack Discussion Only up to a quarter inch of new snow reported this morning. The continued loading of a weak snowpack remains a problem. We continue to receive reports of natural slide activity from isolated areas where large wind slabs have built - primarily steep slopes near and above treeline with NW-NE-SE aspects. Two such slides were observed on N-NE aspects near Cameron Pass at 11,300' with 2' crowns and 500' wide. These locations continue to be the area of greatest concern, especially where the wind slabs are perched atop rotten facets. Beware of drifted and loaded slopes, especially on NW-NE-SE aspects at higher elevations. Watch for signs of instability such as cracking, whumpfing, and recent avalanche activity. As the slabs strengthen, avalanches can propagate further and run larger. Consider the consequences of a bad decision before committing to steep slopes. Below treeline away from wind loaded areas, the recent mild temperatures have helped to settle the snowpack. New snow in the forecast will likely cause the avalanche danger to trend upward by Thursday. Avalanche Danger The avalanche danger is CONSIDERABLE on NW-N-NE-E-SE aspects near and above treeline. Human triggered avalanches remain probable on steep heavily wind loaded slopes. The avalanche danger is MODERATE on other aspects and below treeline. Grand Mesa ========== Current Keywords: LOW, MODERATE, avalanche danger, settle, trough, Mountain Weather and Avalanche Forecast for the Grand Mesa Zone Forecast Issued on 12/5/2007 6:18:42 AM Forecaster: John Snook Weather Synopsis Moist flow, with embedded impulses, is setting up for an extended period of mountain snow. The first impulse is expected to arrive late tonight in west-northwest flow that favors the northern and central mountains where snowfall amounts in the 8-12" range are possible by Thursday afternoon. Snowfall is expected to continue through Friday with periods of heavier snow, the timing of which is difficult to define, but the snow will add up by this weekend. Upper-level flow slowly shifts to southwest by Friday as a deep trough digs in over the Great Basin. This will shift the focus of heaviest snow to the southwest mountains. Weather Wednesday Night Thursday Thursday Night Temperature(°F) 34-39 25-30 30-35 Wind Speed(mph) 0-10 10-20 10-20 Wind Direction SW SW W Sky Cover Increasing Overcast Overcast Snow(in) 0 1-3 2-4 Snowpack Discussion Recent mild temperatures have helped to settle the recent storm snow. The avalanche danger is low where new snow fell on bare ground. Shady aspects that, however, held patches of old snow are quite weak and the new snow layers on top may be sensitive to the weight of a backcountry traveler. Watch out for loose avalanches on any slope steeper than about 35 degrees. The most likely place to trigger an avalanche is on high elevation steep N-NE-E aspects. The consequences of being caught in even a small slide could be quite severe if it pushes you into a pile of rocks, stand of trees, or a gully. New snow in the forecast may cause the avalanche danger to trend upward during the next 48 hours. Avalanche Danger The avalanche danger is MODERATE on steep N-NE-E slopes at the higher elevations, where there are underlying pockets of old snow. The danger is LOW on other aspects. San Juan North ============== Current Keywords: , CONSIDERABLE, LOW, MODERATE, avalanche cycle, avalanche danger, avalanche path, avalanche paths, collapsing, facets, natural avalanche, settle, shear, slab, slabs, trough, whumpfing, wind-loaded, windloading, Mountain Weather and Avalanche Forecast for the Northern San Juan Mountain Zone Forecast Issued on 12/5/2007 6:22:23 AM Forecaster: Mark Rikkers Weather Synopsis Moist flow, with embedded impulses, is setting up for an extended period of mountain snow. The first impulse is expected to arrive late tonight in west-northwest flow that favors the northern and central mountains where snowfall amounts in the 8-12" range are possible by Thursday afternoon. Snowfall is expected to continue through Friday with periods of heavier snow, the timing of which is difficult to define, but the snow will add up by this weekend. Upper-level flow slowly shifts to southwest by Friday as a deep trough digs in over the Great Basin. This will shift the focus of heaviest snow to the southwest mountains. Weather Wednesday Night Thursday Thursday Night Temperature(°F) 32-37 22-27 27-32 Wind Speed(mph) 5-15 10-20 G35 15-25 G35 Wind Direction W SW WSW Sky Cover Mostly Cloudy Overcast Overcast Snow(in) 0 1-3 4-6 Snowpack Discussion Recent mild weather is helping to quickly settle the weekend snow. Observers continue to report a strengthening snowpack, but collapsing and moderate shear results in test pits are still being reported as well. The largest concern remains on NW-N-NE aspects where cohesionless facets underlie the recent slabs, some of which are quite deep due to windloading during the previous storm. Aside from loose activity coming out of steep, sunny aspects with rock or tree outcroppings, our natural avalanche cycle is effectively over. However, reports of triggered avalanches continue. Telluride snow safety got significant results out of 5 avalanche paths yesterday. All slid on northerly aspects (N and NW) between 11,200' and 11,800' and one was a hard slab that ran 5' deep, 400' wide and 700' vertical. Winds have been out of the north recently and have been strong enough to stiffen slabs on northerly slopes and transport snow onto southerly slopes. Recent winds have created hard slab conditions in many areas, even in open areas below treeline. Hard slab can be tricky and dangerous. When you're traveling on it, it can feel "stable" because it is so firm - you can't even jam your pole through it. But hard slab avalanches can be triggered from far away - including from directly below the avalanche path! - and the fractures can propagate over long distances because the slab is so cohesive. Also, hard slab debris tends to be comprised of large chunks that can make an effective rescue particularly challenging. While you are traveling in the backcountry, monitor for signs of instability such as cracking and whumpfing - indicators that the slab you are traveling on has facets underneath that are weak and have the potential to initiate an avalanche. Prior to going out onto a steep slope, check the snowpack for a weak lower layer. Unstable slabs still exist on steep NW-N-NE facing aspects. Consider the consequences of being caught in even a small slide. Although the avalanche danger has trended downward, new snow (bring it!) in the forecast will likely reverse this trend in the next 48 hours. Avalanche Danger The avalanche danger continues to be CONSIDERABLE on NW-N-NE aspects at all elevations. On E and W aspects, the danger is MODERATE near and above treeline and LOW below treeline. On SE-S-SW aspects, the danger is MODERATE above treeline and LOW near and below treeline. Unstable slabs are still probable on steep, wind-loaded northerly terrain. Please contact us with any observations from the field at caic@qwest.net San Juan South ============== Current Keywords: LOW, MODERATE, avalanche danger, facets, natural, path, settle, slabs, surface hoar, trough, weak layer, windloaded, Mountain Weather and Avalanche Forecast for the Southern San Juan Mountain Zone Forecast Issued on 12/5/2007 6:19:04 AM Forecaster: John Snook Weather Synopsis Moist flow, with embedded impulses, is setting up for an extended period of mountain snow. The first impulse is expected to arrive late tonight in west-northwest flow that favors the northern and central mountains where snowfall amounts in the 8-12" range are possible by Thursday afternoon. Snowfall is expected to continue through Friday with periods of heavier snow, the timing of which is difficult to define, but the snow will add up by this weekend. Upper-level flow slowly shifts to southwest by Friday as a deep trough digs in over the Great Basin. This will shift the focus of heaviest snow to the southwest mountains. Weather Wednesday Night Thursday Thursday Night Temperature(°F) 37-42 25-30 28-33 Wind Speed(mph) 5-15 10-20 10-20 Wind Direction W SW SW Sky Cover Mostly Cloudy Overcast Overcast Snow(in) 0 1-3 4-6 Snowpack Discussion Recent mild weather is helping to quickly settle the weekend snow. An observer on Tuesday noted several natural loose slides on high SW aspects. With one more mild day in store, riders will need to monitor afternoon surface snow conditions on sunny aspects. If the surface gets soft and unsupportable on steep slopes, then move to shadier aspects or slopes less than 30 degrees. The other concern remains on N-NE-E aspects where pre-existing old facets underlie the recent snowfall. The same observer noted on Monday a sizeable skier triggered avalanche on the N facing Hour Glass path at 11,400'. Prior to jumping onto a steep slope, check the snowpack for a weak lower layer. Unstable slabs still exist on steep N-NE-E facing aspects. Fresh surface hoar was observed Tuesday morning. Not a problem now, but could become one as a future buried weak layer. New snow in the forecast will likely cause the avalanche danger to trend upward after Wednesday. Join the fun at a CAIC fundraiser tonight at Steamworks Brewery in Durango from 6-9pm. Avalanche Danger The avalanche danger is LOW with pockets of MODERATE on steep N-NE-E aspects near and above treeline. Watch for steep pockets of windloaded snow with old facets underneath. Also watch for afternoon loose slide activity on sunny aspects. Sangre de Christo ================= Current Keywords: avalanche danger, facets, settled, slabs, trough, whumpfing, Mountain Weather and Avalanche Forecast for the Sangre De Cristo Zone Forecast Issued on 12/5/2007 6:19:30 AM Forecaster: John Snook Weather Synopsis Moist flow, with embedded impulses, is setting up for an extended period of mountain snow. The first impulse is expected to arrive late tonight in west-northwest flow that favors the northern and central mountains where snowfall amounts in the 8-12" range are possible by Thursday afternoon. Snowfall is expected to continue through Friday with periods of heavier snow, the timing of which is difficult to define, but the snow will add up by this weekend. Upper-level flow slowly shifts to southwest by Friday as a deep trough digs in over the Great Basin. This will shift the focus of heaviest snow to the southwest mountains. Weather Wednesday Night Thursday Thursday Night Temperature(°F) 37-42 25-30 28-33 Wind Speed(mph) 5-15 10-20 G35 15-25 G40 Wind Direction SW SW WSW Sky Cover Mostly Cloudy Mostly Cloudy Mostly Cloudy Snow(in) 0 1-3 2-4 Snowpack Discussion Recent mild temperatures have likely settled the recent storm snow. The largest concern remains on N-NE-E aspects where pre-existing old facets underlie the recent snowfall. Monitor for signs of instability such as cracking and whumpfing - indicators that old facets underneath are still primed to rip out. Prior to jumping onto a steep slope, check the snowpack for a weak lower layer. Unstable slabs likely exist on steep N-NW-E facing aspects. Consider the consequences of being caught in even a small slide. New snow in the forecast may cause the avalanche danger to trend upward during the next 48 hours. 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 [59]caic@qwest.net Sawatch ======= Current Keywords: CONSIDERABLE, LOW, MODERATE, avalanche danger, drifted, facets, natural, settle, slabs, trough, whumpfing, wind loaded, wind slabs, wind-loaded, Mountain Weather and Avalanche Forecast for the Sawatch Range Zone Forecast Issued on 12/5/2007 6:19:57 AM Forecaster: John Snook Weather Synopsis Moist flow, with embedded impulses, is setting up for an extended period of mountain snow. The first impulse is expected to arrive late tonight in west-northwest flow that favors the northern and central mountains where snowfall amounts in the 8-12" range are possible by Thursday afternoon. Snowfall is expected to continue through Friday with periods of heavier snow, the timing of which is difficult to define, but the snow will add up by this weekend. Upper-level flow slowly shifts to southwest by Friday as a deep trough digs in over the Great Basin. This will shift the focus of heaviest snow to the southwest mountains. Weather Wednesday Night Thursday Thursday Night Temperature(°F) 30-35 22-27 25-30 Wind Speed(mph) 10-20 10-20 G35 15-25 G40 Wind Direction W WSW W Sky Cover Increasing Overcast Overcast Snow(in) 0 4-6 4-6 Snowpack Discussion The continued loading of a weak snowpack remains a problem. We continue to receive reports of natural slide activity from isolated areas where large wind slabs have built - primarily steep slopes near and above treeline with NW-NE-SE aspects. These locations continue to be the area of greatest concern, especially where the wind slabs are perched atop rotten facets. Beware of drifted and loaded slopes, especially on NW-NE-SE aspects at higher elevations. Watch for signs of instability such as cracking, whumpfing, and recent avalanche activity. As the slabs strengthen, avalanches can propagate further and run larger. Consider the consequences of a bad decision before committing to steep slopes. Below treeline away from wind loaded areas, the recent mild temperatures have helped to settle the snowpack. Our observer on Tuesday toured around the Monarch Pass area. He noted that the snowpack in the southern portion of the zone is thinner and less wind-affected than in northern areas of the zone. For the zone the avalanche danger remains at MODERATE with pockets of CONSIDERABLE near and above treeline on NW-NE-SE aspects. Locally around the Monarch Pass area the hazard is LOW with pockets of MODERATE on NW-NE-SE aspects near and above treeline. New snow in the forecast will likely cause the avalanche danger to trend upward by Thursday. Avalanche Danger The danger in the Sawatch zone is MODERATE with pockets of CONSIDERABLE on NW-N-NE-E-SE aspects near and above treeline. Watch for pockets of unstable slabs on steep, wind-loaded slopes. Please [59]send us observations if you are getting out. Steamboat ========= Current Keywords: LOW, MODERATE, avalanche danger, drifted, facets, natural, settled, trough, whumpfing, wind slabs, Mountain Weather and Avalanche Forecast for the Steamboat and Parks Range Zone Forecast Issued on 12/5/2007 6:15:56 AM Forecaster: John Snook Weather Synopsis Moist flow, with embedded impulses, is setting up for an extended period of mountain snow. The first impulse is expected to arrive late tonight in west-northwest flow that favors the northern and central mountains where snowfall amounts in the 8-12" range are possible by Thursday afternoon. Snowfall is expected to continue through Friday with periods of heavier snow, the timing of which is difficult to define, but the snow will add up by this weekend. Upper-level flow slowly shifts to southwest by Friday as a deep trough digs in over the Great Basin. This will shift the focus of heaviest snow to the southwest mountains. Weather Wednesday Night Thursday Thursday Night Temperature(°F) 33-38 20-25 25-30 Wind Speed(mph) 5-15 10-20 15-25 Wind Direction WSW WSW W Sky Cover Increasing Overcast Overcast Snow(in) 0 4-6 4-6 Snowpack Discussion We have not received any recent reports of avalanche activity. The recent mild temperatures have likely settled the snowpack somewhat. But winds have remained strong during the past several days. In neighboring zones, we continue to receive reports of natural slide activity from isolated areas where large wind slabs have built - primarily on high-alpine steep slopes on NW-NE-SE aspects. These locations continue to be the area of greatest concern, especially where the wind slabs are perched atop rotten facets. Beware of drifted and loaded slopes, especially on NW-NE-SE aspects at higher elevations. Watch for signs of instability such as cracking, whumpfing, and recent avalanche activity. Consider the consequences of a bad decision before committing to steep slopes. New snow in the forecast will likely cause the avalanche danger to trend upward by Thursday. Avalanche Danger The avalanche danger in the Steamboat Zone is MODERATE on steep NW-N-NE-E aspects at higher elevations. On other aspects the avalanche danger is LOW. Vail ==== Current Keywords: CONSIDERABLE, MODERATE, avalanche danger, drifted, facets, human triggered avalanches, natural, settle, slabs, trough, whumpfing, wind loaded, wind slabs, Mountain Weather and Avalanche Forecast for the Vail and Summit County Zone Forecast Issued on 12/5/2007 6:16:58 AM Forecaster: John Snook Weather Synopsis Moist flow, with embedded impulses, is setting up for an extended period of mountain snow. The first impulse is expected to arrive late tonight in west-northwest flow that favors the northern and central mountains where snowfall amounts in the 8-12" range are possible by Thursday afternoon. Snowfall is expected to continue through Friday with periods of heavier snow, the timing of which is difficult to define, but the snow will add up by this weekend. Upper-level flow slowly shifts to southwest by Friday as a deep trough digs in over the Great Basin. This will shift the focus of heaviest snow to the southwest mountains. Weather Wednesday Night Thursday Thursday Night Temperature(°F) 27-32 18-23 23-28 Wind Speed(mph) 10-20 15-25 G35 15-25 G40 Wind Direction W W W Sky Cover Increasing Overcast Overcast Snow(in) 0 4-6 4-6 Snowpack Discussion Early reports indicate not more than a quarter inch of new snow overnight. The continued loading of a weak snowpack remains a problem. We continue to receive reports of natural slide activity from isolated areas where large wind slabs have built - primarily steep slopes near and above treeline with NW-NE-SE aspects. These locations continue to be the area of greatest concern, especially where the wind slabs are perched atop rotten facets. Beware of drifted and loaded slopes, especially on NW-NE-SE aspects at higher elevations. Watch for signs of instability such as cracking, whumpfing, and recent avalanche activity. As the slabs strengthen, avalanches can propagate further and run larger. Consider the consequences of a bad decision before committing to steep slopes. Below treeline away from wind loaded areas, the recent mild temperatures have helped to settle the snowpack. New snow in the forecast will likely cause the avalanche danger to trend upward by Thursday. Avalanche Danger The avalanche danger is CONSIDERABLE on NW-N-NE-E-SE aspects near and above treeline. Human triggered avalanches remain probable on steep heavily wind loaded slopes. The avalanche danger is MODERATE on other aspects and below treeline.