Aspen ===== Current Keywords: CONSIDERABLE, Human triggered avalanches, MODERATE, avalanche danger, collapse , faceted, high pressure, human triggered avalanches, path, slab, sugary, surface hoar, wind slabs, Mountain Weather and Avalanche Forecast for the Aspen Zone Forecast Issued on 1/23/2008 6:42:10 AM Forecaster: Scott Toepfer Weather Synopsis High pressure that was influencing the central and southern portion of the state the last 12 hours has finally started to push into the northern zones this afternoon. It really is not bringing a great deal of warm weather with it. It is January, so we are not far off the temperature norms. The high pressure is not long lived as the next in the continuing stream of storms moves into the San Juan on Thursday. Storm duration for the southern mountains looks to last into mid-day Friday, when the flow shifts more west to favor the northern and central zones. Winds once again will play a role as they begin to ramp up for the San Juans on Thursday, and increase in the northern portions by Thursday night. The over-riding weather influence at this time is a persnickity closed low off the west coast. Models wobble the thing up and down the coast for the next 48 plus hours. It seems to be having some difficulty in finding its right path in life. Where it wobbles to, and when, will play a good part in our upcoming snow totals and locations. Another short lived high pressure ridge is currently forecast for Saturday. Weather Wednesday Wednesday Night Thursday Temperature(°F) 15-20 -2 to 3 19-24 Wind Speed(mph) 11-21 3-13 8-18 Wind Direction WNW W SW Sky Cover Mostly Cloudy Partly Cloudy Increasing Snow(in) 0-1 0 0-2 Snowpack Discussion Several inches of new snow fell across the much of the Aspen Zone since Monday morning. Periods of moderate south and southwest winds transported plenty of snow near and above treeline. Fresh wind slabs in the upper snowpack are one of your concerns for avalanche activity on exposed terrain facing N-NE-E-SE. On many of these aspects you can find a thin layer of surface hoar or small, "sugary", faceted snow grains under the wind slabs that will make them very sensitive and easy to trigger. Paths that saw avalanche activity earlier this month have been reloaded with wind deposited snow and may be ripe for avalanche activity again. The danger on the eastern half of the compass near and above treeline has been rated at CONSIDERABLE for some time now, and I cannot lower it due to the continued concern for deep slab instabilities. The troublesome hard slab over weak snow combination can be found on northeast, east, southeast, south, through southwest aspects. You are most likely to trigger a deep slab slide by finding a thin spot in the hard slab itself. Beneath the hard slab is weak faceted grained sugar snow. These instabilities may be localized and are more common near rock outcroppings, downed timber, and cliff bands. The hard slab will support you in some locations and it will give you the impression that the slope is safe. But if you find the thin spot, you can collapse the deck of cards and start a deep slab avalanche. Be particularly aware of potential consequences. Avoid steep slopes that could carry you over cliff bands or into trees. Several recent slides have occurred within terrain traps such as creek drainages. These slides have been short in length, but deep with debris. Your chances of surviving a burial under more than 6 deep of debris are minimal. You need to choose your terrain judiciously. Avalanches do not care how good of a rider you are and especially do not care if you are a local. Avalanche Danger The avalanche danger is CONSIDERABLE on north, northeast, east, and southeast aspects near and above treeline. Upper snowpack slides involving reactive wind slabs and deep slab instabilities are the two concerns. Human triggered avalanches are probable in these areas. The avalanche danger on all other aspects near and above treeline and all slopes below treeline is MODERATE. Human triggered avalanches are still possible on these slopes as well. The CAIC Aspen office needs your backcountry avalanche, weather, or snowpack observations. These are a great help to our forecasters. Please drop us an e-mail at caic@qwest.net with anything you are seeing in the backcountry. Front Range =========== Current Keywords: CONSIDERABLE, MODERATE, avalanche danger, collapse , cross loading, faceted, facets, high pressure, human triggered avalanches, natural, path, shears, slab, slabs, wind slabs, Mountain Weather and Avalanche Forecast for the Front Range Zone Forecast Issued on 1/23/2008 6:35:35 AM Forecaster: Scott Toepfer Weather Synopsis High pressure that was influencing the central and southern portion of the state the last 12 hours has finally started to push into the northern zones this afternoon. It really is not bringing a great deal of warm weather with it. It is January, so we are not far off the temperature norms. The high pressure is not long lived as the next in the continuing stream of storms moves into the San Juan on Thursday. Storm duration for the southern mountains looks to last into mid-day Friday, when the flow shifts more west to favor the northern and central zones. Winds once again will play a role as they begin to ramp up for the San Juans on Thursday, and increase in the northern portions by Thursday night. The over-riding weather influence at this time is a persnickity closed low off the west coast. Models wobble the thing up and down the coast for the next 48 plus hours. It seems to be having some difficulty in finding its right path in life. Where it wobbles to, and when, will play a good part in our upcoming snow totals and locations. Another short lived high pressure ridge is currently forecast for Saturday. Weather Wednesday Wednesday Night Thursday Temperature(°F) 5-10 -2 to 3 15-20 Wind Speed(mph) 20-30 G40 12-22 G30 10-20 G30 Wind Direction W W WSW Sky Cover Mostly Cloudy Mostly Clear Increasing Snow(in) 1-3 0 0-1 Snowpack Discussion A natural slide in the northwest portion of the zone was reported west of Hwy 125 (just north of US Hwy 40) on an ESE aspect at 8600'. An observer on Monday on Stanley Ridge near Berthoud Pass found a 2' base layer of facets, topped by an 8" layer of uncohesive 4-finger snow, and an 8" hard slab on top with easy shears between the top two layers. About 4" of new snow was reported near Berthoud Pass since Tuesday morning. Westerly winds continue to be gusty at times and more strong winds remain in the forecast, especially along and east of the Continental Divide. Shallow slabs are building on easterly slopes and cross loading gullies on northerly and southerly aspects. The danger on the eastern half of the compass near and above treeline has been rated at CONSIDERABLE for some time now, and I cannot lower it due to the continued concern for deep slab instabilities. The troublesome hard slab over weak snow combination can be found on northeast, east, southeast, south, through southwest aspects. You are most likely to trigger a deep slab slide by finding a thin spot in the hard slab itself. Beneath the hard slab is weak faceted grained sugar snow. These instabilities may be localized and are more common near rock outcroppings, downed timber, and cliff bands. The hard slab will support you in some locations and it will give you the impression that the slope is safe. But if you find the thin spot, you can collapse the deck of cards and start a deep slab avalanche. Be particularly aware of potential consequences. Avoid steep slopes that could carry you over cliff bands or into trees. Several recent slides have occurred within terrain traps such as creek drainages. These slides have been short in length, but deep with debris. Your chances of surviving a burial under more than 6 feet of debris are minimal. Avalanche Danger The avalanche danger is CONSIDERABLE on northeast, east, southeast, and south aspects near and above treeline. Upper snowpack slides involving reactive wind slabs and deep slab instabilities are the two concerns. Human triggered avalanches are probable in these areas. Elsewhere and below treeline the danger is MODERATE. Grand Mesa ========== Current Keywords: LOW, MODERATE, avalanche danger, density, high pressure, human triggered, human triggered avalanches, lee , path, slabby, slabs, sluffing, wind transported, wind-loaded, Mountain Weather and Avalanche Forecast for the Grand Mesa Zone Forecast Issued on 1/23/2008 6:00:55 AM Forecaster: Scott Toepfer Weather Synopsis High pressure that was influencing the central and southern portion of the state the last 12 hours has finally started to push into the northern zones this afternoon. It really is not bringing a great deal of warm weather with it. It is January, so we are not far off the temperature norms. The high pressure is not long lived as the next in the continuing stream of storms moves into the San Juan on Thursday. Storm duration for the southern mountains looks to last into mid-day Friday, when the flow shifts more west to favor the northern and central zones. Winds once again will play a role as they begin to ramp up for the San Juans on Thursday, and increase in the northern portions by Thursday night. The over-riding weather influence at this time is a persnickity closed low off the west coast. Models wobble the thing up and down the coast for the next 48 plus hours. It seems to be having some difficulty in finding its right path in life. Where it wobbles to, and when, will play a good part in our upcoming snow totals and locations. Another short lived high pressure ridge is currently forecast for Saturday. Weather Wednesday Wednesday Night Thursday Temperature(°F) 18-23 5-10 18-23 Wind Speed(mph) 0-10 0-10 0-10 Wind Direction WNW SSW SSW Sky Cover Partly Cloudy Mostly Clear Increasing Snow(in) 0 0 0-2 Snowpack Discussion A narrow band of heavier snow fell on the Grand Mesa early Tuesday morning with up to 11" of low density snow reported. Our observer noted some minor sluffing of the new snow and plenty of wind transported snow to lee aspects from north through east. The wind has created a slabby snow surface in exposed areas. Human triggered slides within the upper portions of the snowpack remain possible on steep exposed slopes especially where fresh wind slabs have developed. Before committing to a steep slope, you should evaluate how well the upper layers are bonding and consider the consequences should even a small slide develop. Avalanche Danger The avalanche danger for the Grand Mesa zone is MODERATE on north, northeast, east, southeast, and south aspects near and above treeline. Human triggered avalanches are possible, especially on wind-loaded slopes 35 degrees and steeper. The danger is LOW on other near and above treeline aspects and all aspects below treeline. Please send observations from this or any other zone to [57]caic@qwest.net San Juan North ============== Current Keywords: CONSIDERABLE, Human triggered, MODERATE, avalanche danger, cross-loaded, crown, facets, high pressure, lee , natural, naturals, path, slab, wind slab, wind slabs, windslab, Mountain Weather and Avalanche Forecast for the Northern San Juan Mountain Zone Forecast Issued on 1/23/2008 6:37:38 AM Forecaster: Mark Rikkers Weather Synopsis High pressure that was influencing the central and southern portion of the state the last 12 hours has finally started to push into the northern zones this afternoon. It really is not bringing a great deal of warm weather with it. It is January, so we are not far off the temperature norms. The high pressure is not long lived as the next in the continuing stream of storms moves into the San Juan on Thursday. Storm duration for the southern mountains looks to last into mid-day Friday, when the flow shifts more west to favor the northern and central zones. Winds once again will play a role as they begin to ramp up for the San Juans on Thursday, and increase in the northern portions by Thursday night. The over-riding weather influence at this time is a persnickity closed low off the west coast. Models wobble the thing up and down the coast for the next 48 plus hours. It seems to be having some difficulty in finding its right path in life. Where it wobbles to, and when, will play a good part in our upcoming snow totals and locations. Another short lived high pressure ridge is currently forecast for Saturday. Weather Wednesday Wednesday Night Thursday Temperature(°F) 12-17 7-12 15-20 Wind Speed(mph) 10-20 G30 10-20 G30 10-20 G30 Wind Direction WSW S S Sky Cover Mostly Clear Increasing Overcast Snow(in) 0 0-1 3-5 Snowpack Discussion Consistent south to southwest winds over the past few days transported significant amounts of snow and firmly established the latest wind-affected layer on our upper snowpack. Since then, a flurry of new slide activity, both natural and human triggered, has been reported. The slides have been confined to this fresh and reactive wind slab layer, with fractures roughly ranging from less than a foot to two-feet deep. A majority of the reported avalanches occurred well above treeline, where the wind has the greatest effect, but with gusts into the 60s on Sunday and Monday, the wind worked on open slopes at all elevations and on all aspects. On Monday, a skier triggered a hard windslab with an 18" crown that propagated the full width of a northeast-facing couloir on Yellow Mountain near Ophir - the slide was reported to be about 75' wide, with hard slab chunks that ran about 800' vertical. In addition to natural slides on high, lee northerly aspects, cross-loaded terrain features on west and east aspects were active as well. Inter-basin winds interact with terrain features and on this scale, wind directions and speeds become chaotic. Regardless of aspect, the windslab has been forming on top of near-surface facets from recent cold weather. These grains, though small and making up only a relatively thin layer, are cohesionless and do not make for a good bonding interface. Avalanche activity resulting from recent winds has not been limited to areas above treeline. Several naturals along Red Mountain Pass involved crossloaded terrain features on west and east aspects, mostly near and below treeline. These slides were also confined to the upper layer wind slab and were generally 1' deep or less and not more than 30' wide. Remote weather stations are showing that ridgetop winds have started to trend from the southwest toward the west this morning, with averages in the teens and gusts into the 20s. While many areas above treeline have been scoured, there is still plenty of snow up high to be transported at these speeds. With new snow and gusty southerly winds picking up tomorrow, we will have an already tender upper snowpack being loaded once again. Before committing to a steep slope, you should evaluate how well the upper layers are bonding and consider the consequences should even a small slide develop. With a complex and multi-layered snowpack, particularly near and above treeline, avalanche activity in the next few days is likely to initiate in the uppermost layer of the snowpack. But remember - once moving, any avalanche will have the potential to step down deeper into other layers that are, for now, clinging on to steep slopes. Avalanche Danger Near and above treeline, the avalanche danger for the Northern San Juan zone is CONSIDERABLE on all aspects. Human triggered upper snowpack slides involving fresh reactive wind slabs are probable on steep slopes in these areas. Below treeline, the danger is MODERATE on all aspects. San Juan South ============== Current Keywords: LOW, MODERATE, avalanche danger, cross loaded, drifts, facets, high pressure, human triggered, lee , natural, path, settled, weak layer, weak layers, wind slabs, Mountain Weather and Avalanche Forecast for the Southern San Juan Mountain Zone Forecast Issued on 1/23/2008 6:02:02 AM Forecaster: Scott Toepfer Weather Synopsis High pressure that was influencing the central and southern portion of the state the last 12 hours has finally started to push into the northern zones this afternoon. It really is not bringing a great deal of warm weather with it. It is January, so we are not far off the temperature norms. The high pressure is not long lived as the next in the continuing stream of storms moves into the San Juan on Thursday. Storm duration for the southern mountains looks to last into mid-day Friday, when the flow shifts more west to favor the northern and central zones. Winds once again will play a role as they begin to ramp up for the San Juans on Thursday, and increase in the northern portions by Thursday night. The over-riding weather influence at this time is a persnickity closed low off the west coast. Models wobble the thing up and down the coast for the next 48 plus hours. It seems to be having some difficulty in finding its right path in life. Where it wobbles to, and when, will play a good part in our upcoming snow totals and locations. Another short lived high pressure ridge is currently forecast for Saturday. Weather Wednesday Wednesday Night Thursday Temperature(°F) 15-20 5-10 15-20 Wind Speed(mph) 10-20 G30 10-20 G30 10-20 G30 Wind Direction WSW SW SSW Sky Cover Mostly Clear Increasing Overcast Snow(in) 0-1 0-2 3-5 Snowpack Discussion The snowpack in the Wolf Creek Pass area has settled and gained strength. Winds on Tuesday continued to be strong enough from the south-southwest to transport available snow onto lee northerly aspects and cross loaded terrain features on westerly and easterly aspects. Steep, exposed slopes on these aspects near and above treeline are the most suspect terrain for human triggered slides within recently developed wind slabs. Before committing to a steep slope, you should evaluate how well the upper layers are bonding and consider the consequences should even a small slide develop. Observers along the Highway 550 corridor north of Durango to Silverton have noted more weak layers and resultant activity. The snowpack is somewhat shallower there and winds have created more noticeable hard wind slabs. Closer to Red Mountain Pass on Monday, a number of smaller natural slides released from cross loaded west and east facing aspects. Recent cold temperatures have created a layer of near surface facets. Now wind slabs are forming on top of this cohesionless layer. You need to be careful in this part of the zone where fresh wind slabs have formed on steep exposed slopes. Avalanche Danger The avalanche danger is overall MODERATE near and above treeline. Human triggered slides are possible on steep exposed slopes where fresh wind slabs have developed on many aspects. In the Wolf Creek Pass area, the danger is LOW below treeline. North of Durango along the Highway 550 corridor, the danger is MODERATE below treeline on west-north-east aspects where the snowpack is shallower and fresh wind drifts may be forming on a weak layer of near surface facets. Sangre de Christo ================= Current Keywords: CONSIDERABLE, MODERATE, avalanche danger, cross loaded, faceted, facets, high pressure, human triggered, lee , path, slab, wind drifted, wind loaded, wind slabs, windslabs, Mountain Weather and Avalanche Forecast for the Sangre De Cristo Zone Forecast Issued on 1/23/2008 6:03:12 AM Forecaster: Scott Toepfer Weather Synopsis High pressure that was influencing the central and southern portion of the state the last 12 hours has finally started to push into the northern zones this afternoon. It really is not bringing a great deal of warm weather with it. It is January, so we are not far off the temperature norms. The high pressure is not long lived as the next in the continuing stream of storms moves into the San Juan on Thursday. Storm duration for the southern mountains looks to last into mid-day Friday, when the flow shifts more west to favor the northern and central zones. Winds once again will play a role as they begin to ramp up for the San Juans on Thursday, and increase in the northern portions by Thursday night. The over-riding weather influence at this time is a persnickity closed low off the west coast. Models wobble the thing up and down the coast for the next 48 plus hours. It seems to be having some difficulty in finding its right path in life. Where it wobbles to, and when, will play a good part in our upcoming snow totals and locations. Another short lived high pressure ridge is currently forecast for Saturday. Weather Wednesday Wednesday Night Thursday Temperature(°F) 12-17 5-10 15-20 Wind Speed(mph) 26-36 15-25 16-26 Wind Direction W W SW Sky Cover Mostly Clear Increasing Mostly Cloudy Snow(in) 0 0 0-1 Snowpack Discussion Our forecasters were in the Sangres a little over a week ago. They found an above treeline snowpack comprised largely of stiff hard windslabs resting on weak faceted layers or the snow was missing all together where winds have transported it onto lee terrain. The most suspect slopes are wind drifted and cross loaded north through east through south aspects. An observer in the Sangres of New Mexico found two layers of facets in test pits below treeline. Each layer was about 1' deep with larger facets in the base layer and smaller facets in the upper layer. The Sangres have a relatively shallow snowpack. The primary concern in neighboring zones with shallow snowpacks is deep slab instabilities. These instabilities may be localized. The stiff wind slabs will hold your weight in many areas, but you can breakthrough on weak spots especially near cliffs, rock outcroppings and vegetation. If you do trigger a slide from a weak spot, it could cause the entire snowpack to slide creating a large avalanche. As you travel, constantly reevaluate the snowpack for signs of these instabilities. Avalanche Danger The avalanche danger in the Sangre de Cristo Zone is CONSIDERABLE near and above treeline on NE-E-SE-SW aspects and MODERATE near and below treeline on the other aspects, W-NW-N. Human triggered slides are possible to probable today. Carefully evaluate steep wind loaded slopes. Please send observations from this or any other zone to [57]caic@qwest.net Sawatch ======= Current Keywords: CONSIDERABLE, LOW, MODERATE, avalanche danger, collapse , cross load, cross-loaded, faceted, high pressure, human triggered, natural, path, slab, slabs, wind loaded, wind slab, wind slabs, Mountain Weather and Avalanche Forecast for the Sawatch Range Zone Forecast Issued on 1/23/2008 6:03:41 AM Forecaster: Scott Toepfer Weather Synopsis High pressure that was influencing the central and southern portion of the state the last 12 hours has finally started to push into the northern zones this afternoon. It really is not bringing a great deal of warm weather with it. It is January, so we are not far off the temperature norms. The high pressure is not long lived as the next in the continuing stream of storms moves into the San Juan on Thursday. Storm duration for the southern mountains looks to last into mid-day Friday, when the flow shifts more west to favor the northern and central zones. Winds once again will play a role as they begin to ramp up for the San Juans on Thursday, and increase in the northern portions by Thursday night. The over-riding weather influence at this time is a persnickity closed low off the west coast. Models wobble the thing up and down the coast for the next 48 plus hours. It seems to be having some difficulty in finding its right path in life. Where it wobbles to, and when, will play a good part in our upcoming snow totals and locations. Another short lived high pressure ridge is currently forecast for Saturday. Weather Wednesday Wednesday Night Thursday Temperature(°F) 12-17 3-8 15-20 Wind Speed(mph) 15-25 15-25 15-25 Wind Direction W W WSW Sky Cover Partly Cloudy Increasing Mostly Cloudy Snow(in) 0 0 1-3 Snowpack Discussion Reports of slide activity have slowed during the past few days. The most recent reported slide was on Sunday - a human triggered soft slab on an east aspect just above treeline near Monarch Pass. Another report of a larger sized natural slab avalanche occurred in the same area but on a NE aspect. We suspect it occurred on Sunday as well. A little new snow and moderate wind speeds remain in the forecast. The westerly winds will continue to add shallow slabs onto easterly aspects and cross load northerly and southerly facing terrain features. You could trigger a recently developed wind slab on steep exposed north through east through south facing slopes. Persistent deep slab instability concerns remain in the picture. The troublesome hard slab over weak snow combination can be found on northeast, east, southeast, south, through southwest aspects. You are most likely to trigger a deep slab slide by finding a thin spot in the hard slab itself. Beneath the hard slab is weak faceted grained sugar snow. These instabilities may be localized and are more common near rock outcroppings, downed timber, and cliff bands. The hard slab will support you in some locations and it will give you the impression that the slope is safe. But if you find the thin spot, you can collapse the deck of cards and start a deep slab avalanche. Be particularly aware of potential consequences. Avoid steep slopes that could carry you over cliff bands or into trees. Several recent slides have occurred within terrain traps such as creek drainages. These slides have been short in length, but deep with debris. Your chances of surviving a burial under more than 6 deep of debris are minimal. You need to choose your terrain judiciously. Avalanches do not care how good of a rider you are and especially do not care if you are a local. Avalanche Danger The avalanche danger in the Sawatch Zone includes pockets of CONSIDERABLE on steep wind loaded and cross-loaded slopes on northeast, through southeast and south aspects near and above treeline. Upper snowpack slides involving reactive wind slabs and deep slab instabilities are the two concerns. On other aspects near and above treeline the danger is MODERATE. Below treeline, the danger is LOW on all aspects. [57]Please let us know if you see any avalanche activity or experienced signs of instability. Steamboat ========= Current Keywords: LOW, MODERATE, avalanche danger, collapse , cross loaded, depth hoar, high pressure, natural, path, settle, slab, temperature gradient, wind loading, wind slabs, Mountain Weather and Avalanche Forecast for the Steamboat and Parks Range Zone Forecast Issued on 1/23/2008 4:25:42 PM Forecaster: Scott Toepfer Weather Synopsis High pressure that was influencing the central and southern portion of the state the last 12 hours has finally started to push into the northern zones this afternoon. It really is not bringing a great deal of warm weather with it. It is January, so we are not far off the temperature norms. The high pressure is not long lived as the next in the continuing stream of storms moves into the San Juan on Thursday. Storm duration for the southern mountains looks to last into mid-day Friday, when the flow shifts more west to favor the northern and central zones. Winds once again will play a role as they begin to ramp up for the San Juans on Thursday, and increase in the northern portions by Thursday night. The over-riding weather influence at this time is a persnickity closed low off the west coast. Models wobble the thing up and down the coast for the next 48 plus hours. It seems to be having some difficulty in finding its right path in life. Where it wobbles to, and when, will play a good part in our upcoming snow totals and locations. Another short lived high pressure ridge is currently forecast for Saturday. Weather Wednesday Night Thursday Thursday Night Temperature(°F) -2 to 3 14-19 3-8 Wind Speed(mph) 5-15 10-20 12-22 G30 Wind Direction SW SW WSW Sky Cover Mostly Clear Increasing Overcast Snow(in) 0 2-4 4-7 Snowpack Discussion An observer noted one natural slide on Tuesday in Sleeping Giant #6 - 2' x 150' x 350'. An observer on the south side of Buffalo Pass on Sunday indicated that last week's weather got warm enough to help the snowpack settle. Recent storm snow, from 2 to 13 inches, and wind loading remain the primary concerns. Wind speeds subsided on Tuesday, but they were strong enough from the west-northwest to move snow in exposed areas. You will need to watch for fresh wind slabs and cross loaded terrain features on north through east through south aspects. As the snow continues to add up it is helping with the over all strengthening of the snow pack by reducing the temperature gradient across the depth. This builds rounder grains and bigger inter grain bonds. That is a good thing. Given enough time, even large depth hoar grains will start to round and bond with their neighbors. Time is the big one here, it takes a while. Plus, as we all know, the snowpack does not deposit as a uniform blanket across terrain. Wind, terrain complexity and the direction the storms come from all work to build or strip snow from the ground. Early this season we had some issues with deep slab instability. What we have heard recently from Steamboat Zone observers is that this problem does not seem to be there anymore as the general snowpack builds depth. A problem we might find is getting into areas where winds have built large convex rolls in complex terrain. Lower on the slope, or off to the sides of a path, the snowpack may thin out, allowing riders easier access to weaker layers. If these collapse or fail, we may still see some large full depth avalanches. Our point...Think like an avalanche, where would you like to lurk if you wanted to bite someone. And if it bites where will it drag you. Avalanche Danger The avalanche danger in the Steamboat Zone is MODERATE near and above treeline. Well below treeline, the danger is LOW. If you have any observations or data to share, please send them to [57]caic@qwest.net. Vail ==== Current Keywords: CONSIDERABLE, LOW, MODERATE, avalanche danger, collapse , cornices, cross loaded, faceted, front, high pressure, human triggered, human triggered avalanches, natural, path, slab, slabs, wind slabs, Mountain Weather and Avalanche Forecast for the Vail and Summit County Zone Forecast Issued on 1/23/2008 9:10:47 AM Forecaster: Scott Toepfer Weather Synopsis High pressure that was influencing the central and southern portion of the state the last 12 hours has finally started to push into the northern zones this afternoon. It really is not bringing a great deal of warm weather with it. It is January, so we are not far off the temperature norms. The high pressure is not long lived as the next in the continuing stream of storms moves into the San Juan on Thursday. Storm duration for the southern mountains looks to last into mid-day Friday, when the flow shifts more west to favor the northern and central zones. Winds once again will play a role as they begin to ramp up for the San Juans on Thursday, and increase in the northern portions by Thursday night. The over-riding weather influence at this time is a persnickity closed low off the west coast. Models wobble the thing up and down the coast for the next 48 plus hours. It seems to be having some difficulty in finding its right path in life. Where it wobbles to, and when, will play a good part in our upcoming snow totals and locations. Another short lived high pressure ridge is currently forecast for Saturday. Weather Wednesday Wednesday Night Thursday Temperature(°F) 7-12 -4 to 1 17-22 Wind Speed(mph) 11-21 10-20 10-20 Wind Direction W WSW WSW Sky Cover Mostly Cloudy Partly Cloudy Increasing Snow(in) Tr-2 0 0-1 Snowpack Discussion Reports of slide activity continue to trickle in. The most recent occurred Monday near Vail Pass. Two separate human triggered slides occurred on Ptarmigan Peak. Witnesses of both voiced concerns that the skier and snowboarder exhibited very poor terrain choices. These occurred above tree line, on a south aspect as well as a northeast aspect. A snowmobile triggered slide occurred in the same vicinity above Black Lakes. In the Corral Creek drainage on the other side of the interstate, natural activity was spotted on both north and south aspects below tree line. Most other slides during the past week started near or above treeline on east to south to southwest aspects. A few inches of snow have fallen across the area since Monday morning. Westerly winds continue to be moderate to strong generally from the west, but given terrain features they have also been noted at more northerly. The recent winds continue to build slab on top of weak faceted snow. Southerly aspects north of Montezuma on Tuesday were seeing significant wind deposition and building slab over weak base layers. Northerly aspects at ridgelines had short slab build-up just below cornices and convex rolls which were quite reactive, but did not run far. Its been a cold January, and the snowpack on the whole has turned more faceted/square grained. If our snowpack is all facets, we have few worries about slab avalanches, its the persistant winds that have been keeping the threat of shallow and deep slabs front and center. Traveling across southerly aspects on mid-twenty degree terrain felt very uncomfortable Tuesday. The danger on the eastern half of the compass near and above treeline has been rated at CONSIDERABLE for some time now, and we cannot lower it due to the continued concern for deep slab instabilities. The troublesome hard slab over weak snow combination can be found on northeast, east, southeast, south, through southwest aspects. You are most likely to trigger a deep slab slide by finding a thin spot in the hard slab itself. Beneath the hard slab is weak faceted grained sugar snow. These instabilities may be localized and are more common near rock outcroppings, downed timber, and cliff bands. The hard slab will support you in some locations and it will give you the impression that the slope is safe. But if you find the thin spot, you can collapse the deck of cards and start a deep slab avalanche. Several recent slides have occurred within terrain traps such as creek drainages. These slides have been short in length, but deep with debris. Your chances of surviving a burial under more than 6 deep of debris are minimal. You need to choose your terrain judiciously. Lower angle terrain has been providing excellent riding. Most recent activity has been on terrain over 35 degrees, but we would suggest hard analysis of the terrain before jumping in. Avalanche Danger The avalanche danger in the Vail-Summit Zone is MODERATE with pockets of CONSIDERABLE on slopes steeper than 34 degrees that have been wind loaded or cross loaded facing north, through east, through south, and southwest aspects near and above treeline. Upper snowpack slides involving reactive wind slabs and deep slab instabilities are the two concerns. Human triggered avalanches are probable in these areas. On west and northwest aspects above treeline the danger is LOW as winds have stripped most snow off these aspects. At and below treeline the danger is MODERATE on all aspects.