Aspen ===== Current Keywords: CONSIDERABLE, HIGH, Human triggered, avalanche danger, density, drifts, facets, high pressure, low pressure, slab, slabs, trough, weak layers, Mountain Weather and Avalanche Forecast for the Aspen Zone Forecast Issued on 2/4/2008 6:06:58 AM Forecaster: Scott Toepfer Weather Synopsis The current low pressure trough will cross Colorado tonight on its slow trek eastward. First, a strong impulse of moisture moving NE from New Mexico/Arizona will move into the San Juans and Sangre De Cristos with more snow, but at least winds have shown sign of decreasing as the trough gradually moves east. This stream of moisture will also track up along the east side of the Front Ranges tonight into Tuesday morning. With the shift to northerly winds the focus of snowfall will move into the north and central zones and north side of the San Juan later tonight into Tuesday morning. We will see a gradual drying trend Tuesday afternoon into Tuesday night when a weak high pressure ridge moves overhead. By Wednesday afternoon the next system begins its move into the state. Weather Monday Monday Night Tuesday Temperature(°F) 15-20 -1 to 4 11-16 Wind Speed(mph) 5-15 5-15 10-20 Wind Direction W NW NW Sky Cover Overcast Overcast Mostly Cloudy Snow(in) 7-9 2-4 0-2 Snowpack Discussion Snowfall was modest in the Aspen Zone on Sunday though winds were busy redistributing ample new snow into fresh, slabs and drifts. Several more inches fell Sunday night, though winds are expected to ease in strength over the next 24 hours. Our main avalanche concern lies in the upper layers of the very deep snowpack. Recent slides have primarily been shallow slabs on higher elevation north and easterly aspects. However, deep slab instabilities still exist and slides have the potential to step down to deeper weak layers, especially as the weight of new snow piles up. With recent moderate to strong southwesterly winds, the heaviest loading occurred on northwest, north, northeast, east and southeasterly aspects near and above treeline. Southerly aspects will start loading as winds veer to the northwest on Monday. North through east through south slopes will continue to see the most avalanche activity. Several weak layers exist including buried facets and low density snow that fell earlier in the week. New snow may slide on hard slabs from our last major wind storm as well. Look for continually changing conditions as the storm rolls through. Choose your terrain wisely and be prepared to alter your plans if the snow is touchier than you expected. Avalanche Danger The avalanche danger is HIGH on north, northeast, east, southeast and south aspects. The danger on other aspects and elevations is CONSIDERABLE. Human triggered slides are likely to probable. The CAIC Aspen office needs your backcountry avalanche, weather, and snowpack observations! During storm cycles like this, these observations are very valuable and our forecaster's legs and eyes can only cover so much terrain in one day! You can help out by emailing us at caic@qwest.net with anything you see out there today. Front Range =========== Current Keywords: CONSIDERABLE, MODERATE, avalanche danger, collapse., cornice, density, high pressure, human triggered avalanches, low pressure, rutschblock, slab, slabs, trough, weak layers, whumpfing, wind loaded, windloading, windslabs, Mountain Weather and Avalanche Forecast for the Front Range Zone Forecast Issued on 2/4/2008 5:58:24 AM Forecaster: Scott Toepfer Weather Synopsis The current low pressure trough will cross Colorado tonight on its slow trek eastward. First, a strong impulse of moisture moving NE from New Mexico/Arizona will move into the San Juans and Sangre De Cristos with more snow, but at least winds have shown sign of decreasing as the trough gradually moves east. This stream of moisture will also track up along the east side of the Front Ranges tonight into Tuesday morning. With the shift to northerly winds the focus of snowfall will move into the north and central zones and north side of the San Juan later tonight into Tuesday morning. We will see a gradual drying trend Tuesday afternoon into Tuesday night when a weak high pressure ridge moves overhead. By Wednesday afternoon the next system begins its move into the state. Weather Monday Monday Night Tuesday Temperature(°F) 10-15 -2 to 3 2-7 Wind Speed(mph) 5-15 G20s 5-15 G20s 10-20 G30s Wind Direction WSW N->NE N->W Sky Cover Overcast Overcast Mostly Cloudy Snow(in) 2-4 1-3 Tr-2 Snowpack Discussion Little by little, snow is adding up in the Front Range. On its own, the low-density new snow is not much of a load, especially when applied slowly. Observers in the Berthoud Pass area on Sunday reported a fresh slide on the Current Creek Headwall. This east facing slide cracked 50 feet wide and ran 500 feet down the slope. It occurred on a wind loaded area just below the ridge and may have been triggered by a cornice collapse. East of the Divide and well west of Boulder there was some cracking reported, but no slides observed. Visibility remains limited as winter continues to rule over our mountains. Several fresh slides were spotted on the east facing Loveland Summit Ridge on Sunday, seemingly a direct result of windloading. An observer in the Loveland Pass area on Saturday noted reactive windslabs in the new wind effected snow, with cracks propagating up to 75 feet on east and northeast aspects. Shooting cracks are an excellent indication of instability. Backcountry skiers in the Indian Peaks area triggered a small slab on a southeast aspect near treeline. Others in the area noted stiff slabs, low rutschblock scores and whumpfing. These are all good indications of snowpack instability. Look for them as you travel in the backcountry today. Though an infrequent problem, deep slab instabilities continue to linger as well. Deep slides are often triggered from shallower, weaker areas on the slope. Smaller slides may step down, triggering older weak layers as well. More snow and wind is in the forecast through the weekend, so the avalanche danger will not subside. Avalanche Danger The avalanche danger in the Front Range is CONSIDERABLE on north, northeast, east, southeast and south aspects near and above treeline. Human triggered avalanches are probable on steep wind loaded slopes. Below treeline on north, northeast, east, southeast and south aspects the danger is MODERATE with pockets of CONSIDERABLE danger. Look for pockets on steep exposed slopes, where windslabs formed early in the week. The danger is MODERATE on southwest, west, and northwest aspects at all elevations. Grand Mesa ========== Current Keywords: CONSIDERABLE, avalanche danger, high pressure, low pressure, naturally, precipitation , slab, slabs, trough, Mountain Weather and Avalanche Forecast for the Grand Mesa Zone Forecast Issued on 2/4/2008 6:09:58 AM Forecaster: Scott Toepfer Weather Synopsis The current low pressure trough will cross Colorado tonight on its slow trek eastward. First, a strong impulse of moisture moving NE from New Mexico/Arizona will move into the San Juans and Sangre De Cristos with more snow, but at least winds have shown sign of decreasing as the trough gradually moves east. This stream of moisture will also track up along the east side of the Front Ranges tonight into Tuesday morning. With the shift to northerly winds the focus of snowfall will move into the north and central zones and north side of the San Juan later tonight into Tuesday morning. We will see a gradual drying trend Tuesday afternoon into Tuesday night when a weak high pressure ridge moves overhead. By Wednesday afternoon the next system begins its move into the state. Weather Monday Monday Night Tuesday Temperature(°F) 16-21 -1 to 4 16-21 Wind Speed(mph) 5-15 5-15 5-15 Wind Direction NNW N N Sky Cover Overcast Overcast Mostly Cloudy Snow(in) 7-9 3-5 Tr-2 Snowpack Discussion Moderate to heavy precipitation and strong southwesterly winds are rapidly forming fresh slabs in the Grand Mesa Zone. New snow has fallen on very hard slabs left from last week's storm. A forecaster in the area noted that new snow was not bonding well with this old surface. An observation from Sunday afternoon reported reactive slabs on terrain over 35 degrees, northerly aspects. The fracture propagated quite rapidly. The danger will steadily rise as the snow accumulates and snow will begin to slide naturally when a critical mass is reached. Look for rapid loading on exposed north and easterly aspects from strong and gusty winds. These slopes will be the first to slide. Travel on or below steep slopes is not recommended at this time. We have posted a watch for the Grand Mesa Zone in anticipation of a rapid new load. Look for changing conditions in the backcountry and plan accordingly. As snow builds, the likelihood of slab avalanche will increase as well. Avalanche Danger The avalanche danger in the Grand Mesa Zone is CONSIDERABLE on all aspects and elevations. Natural avalanches are possible and human triggered avalanches are probable. Look for rising danger if forecasted snow totals are met or exceeded. Please send observations from this or any other zone to [57]caic@qwest.net San Juan North ============== Current Keywords: avalanche danger, crusts, density, eXTREME, faceted, high pressure, human triggered avalanches, low pressure, natural, natural avalanche, powder , precipitation , settled, shears, slab, slabs, snowpits, trough, wind loading, wind slabs, Mountain Weather and Avalanche Forecast for the Northern San Juan Mountain Zone Forecast Issued on 2/4/2008 6:28:47 AM Forecaster: Mark Rikkers Weather Synopsis The current low pressure trough will cross Colorado tonight on its slow trek eastward. First, a strong impulse of moisture moving NE from New Mexico/Arizona will move into the San Juans and Sangre De Cristos with more snow, but at least winds have shown sign of decreasing as the trough gradually moves east. This stream of moisture will also track up along the east side of the Front Ranges tonight into Tuesday morning. With the shift to northerly winds the focus of snowfall will move into the north and central zones and north side of the San Juan later tonight into Tuesday morning. We will see a gradual drying trend Tuesday afternoon into Tuesday night when a weak high pressure ridge moves overhead. By Wednesday afternoon the next system begins its move into the state. Weather Monday Monday Night Tuesday Temperature(°F) 8-13 -2 to 3 14-19 Wind Speed(mph) 10-20 G30 5-15 G20 15-25 G40 Wind Direction W->N NNE N Sky Cover Overcast Overcast Mostly Cloudy Snow(in) 6-8 2-4 0-1 Snowpack Discussion Snow totals from Sunday's storm vary by location within our zone, but by the time the Superbowl was over everywhere had its share. The Lizard Head Snotel site, near Telluride, reports 15" of snow and 1.2" of water in the last 24 hours. When these numbers are added to the snowfall we had exactly a week ago, plus a smaller shot of precipitation on Saturday, the totals are in the three-feet range and pushing past three inches of water. Observers reported waves of high precipitation intensity and wind speeds throughout the day and into the night Sunday, though by early Monday morning the weather had settled down. Local weather stations show generally south-southwest flow in the last 24 hours, with wind speeds that are perfect for transporting the massive amounts of available snow. While predominant ridgetop flow has been loading high northerly slopes in particular, complex mountain terrain and chaotic inter-basin winds are causing wind loading on slopes of all aspects and elevations. In short, our snowpack is being put to the test and conditions are tender across the board. The forecast currently calls for an additional 8 to 12 inches of snow by Tuesday morning, when a period of relative clearing is expected. Winds are expected to swap to the west and then to the north through the day Monday, again with perfect transport speeds, guaranteeing loading on all aspects, particularly near and above treeline. Backcountry observers doing tests in snowpits have been reporting fast and clean shears within the top 2 feet of the snowpack. These results indicate obvious weak interfaces within the snowpack and the strong potential for slab avalanches to propagate over long distances. At this point, any slab avalanches that do occur have the potential to step down into deeper layers within the snowpack, causing large and destructive avalanches. Third-hand reports are coming in of observed natural avalanche activity in the backcountry on Monday, though visibility was poor and details are lacking. The snowpack is stacked with wind slabs, density-change interfaces, persistent faceted layers and, on sunny aspects, relatively weak crusts with faceted snow both above and below them. An Avalanche Warning for the Northern San Juan Zone remains in effect. As of Monday morning, Red Mountain, Molas, Coal Bank, Lizard Head and Wolf Creek Passes remain closed due to hazardous avalanche conditions. Travel in the backcountry is not recommended - visit your local ski area and enjoy the epic powder that is undoubtedly waiting for you there. Avalanche Danger An Avalanche Warning is in effect for the Northern San Juan Zone. The avalanche danger is EXTREME on all aspects and elevations. Widespread natural and human triggered avalanches are certain and large, destructive avalanches are possible. Extremely unstable slabs exist on most aspects and slope angles. [57]Please let us know if you see any avalanche activity or experienced signs of instability. San Juan South ============== Current Keywords: density, eXTREME, high pressure, low pressure, slabs, trough, Mountain Weather and Avalanche Forecast for the Southern San Juan Mountain Zone Forecast Issued on 2/4/2008 7:09:04 AM Forecaster: Scott Toepfer Weather Synopsis The current low pressure trough will cross Colorado tonight on its slow trek eastward. First, a strong impulse of moisture moving NE from New Mexico/Arizona will move into the San Juans and Sangre De Cristos with more snow, but at least winds have shown sign of decreasing as the trough gradually moves east. This stream of moisture will also track up along the east side of the Front Ranges tonight into Tuesday morning. With the shift to northerly winds the focus of snowfall will move into the north and central zones and north side of the San Juan later tonight into Tuesday morning. We will see a gradual drying trend Tuesday afternoon into Tuesday night when a weak high pressure ridge moves overhead. By Wednesday afternoon the next system begins its move into the state. Weather Monday Monday Night Tuesday Temperature(°F) 13-18 -3 to 2 18-23 Wind Speed(mph) 10-20 5-15 10-20 Wind Direction SW WSW WSW Sky Cover Overcast Mostly Cloudy Mostly Cloudy Snow(in) 6-8 1-3 0-2 Snowpack Discussion * * * And the snow continues * * * Observers noted steady snow falling an inch to two inches an hour through the day on Sunday and into Sunday night. Southerly winds strong enough to move snow have been rapidly redistributing ample low density snow. More snow is again in the forecast, though winds should finally ease in strength. All mountain roads across the San Juan are closed at this time. Avalanches have run across all the passes, some quite large. This whole mess will take some time to clean-up. All the recent wind and snow adds up to rapid loading of the snowpack on all aspects and elevations, thus we have issued an Avalanche Warning for the Southern San Juan Zone. Highways 550 and 160 over Molas, Coal Bank and Wolf Creek Passes have been closed due to dangerous avalanche conditions as of this writing. Lizard Head Pass is closed as well. The danger in the Wolf Creek Pass area is at Extreme. Unstable slabs are certain on a variety of aspects and slope angles. Access into the backcountry will be difficult at best, especially since most all roads are closed. We recommend avoiding the backcountry at this time. Slides could reach historical size and distance. Avalanche Danger With anticipated pronlonged heavy snow through Monday, the avalanche danger is EXTREME on all aspects and elevations in the Southern San Juan today. Unstable slabs are certain on a variety of aspects and slope angles. [57]Please let us know if you see any avalanche activity or experienced signs of instability. Sangre de Christo ================= Current Keywords: avalanche danger, dense, drifted, high pressure, lee , low pressure, sluffing, trough, wind loaded, windslabs, Mountain Weather and Avalanche Forecast for the Sangre De Cristo Zone Forecast Issued on 2/4/2008 6:16:26 AM Forecaster: Scott Toepfer Weather Synopsis The current low pressure trough will cross Colorado tonight on its slow trek eastward. First, a strong impulse of moisture moving NE from New Mexico/Arizona will move into the San Juans and Sangre De Cristos with more snow, but at least winds have shown sign of decreasing as the trough gradually moves east. This stream of moisture will also track up along the east side of the Front Ranges tonight into Tuesday morning. With the shift to northerly winds the focus of snowfall will move into the north and central zones and north side of the San Juan later tonight into Tuesday morning. We will see a gradual drying trend Tuesday afternoon into Tuesday night when a weak high pressure ridge moves overhead. By Wednesday afternoon the next system begins its move into the state. Weather Monday Monday Night Tuesday Temperature(°F) 9-14 -2-3 10-15 Wind Speed(mph) 11-21 G30 5-15 11-21 Wind Direction NNE NNE N Sky Cover Overcast Overcast Mostly Cloudy Snow(in) 3-5 6-8 0-2 Snowpack Discussion The Sangres may get a good shot of moisture out of the incoming storm, especially on Monday night into Tuesday as winds shift to NE. The range has missed the bulk of the moisture from recent storms, though got more than its share of wind. Persistent and gusty winds have battered the range, redistributing snow onto lee slopes. Expect north through east through southerly aspects to be loaded and drifted. The Sangres have a relatively shallow snowpack, capped by a variety of dense windslabs. If the upper end of snow amounts is met or exceeded, expect rising avalanche danger in the Sangres. New snow will likely not bond well to old hard snow surfaces. Loose snow sluffing will be common. Slides that initiate in the upper snowpack have the potential to break down to weaker basal layers. Travel is not recommended in steep terrain as the snow piles up. As always, we really like to get observations, even if it is just cloud cover and new snow from the valley floors. Avalanche Danger We have insufficient information to issue an avalanche danger for the Sangre De Christo zone. Carefully evaluate steep wind loaded slopes and be very aware of changing conditions. Please send observations from this or any other zone to [57]caic@qwest.net Sawatch ======= Current Keywords: CONSIDERABLE, HIGH, avalanche cycle, avalanche danger, collapses, density, facets, high pressure, low pressure, natural avalanche, slab, slabs, trough, weak layers, wind transport, windslabs, Mountain Weather and Avalanche Forecast for the Sawatch Range Zone Forecast Issued on 2/4/2008 6:18:19 AM Forecaster: Scott Toepfer Weather Synopsis The current low pressure trough will cross Colorado tonight on its slow trek eastward. First, a strong impulse of moisture moving NE from New Mexico/Arizona will move into the San Juans and Sangre De Cristos with more snow, but at least winds have shown sign of decreasing as the trough gradually moves east. This stream of moisture will also track up along the east side of the Front Ranges tonight into Tuesday morning. With the shift to northerly winds the focus of snowfall will move into the north and central zones and north side of the San Juan later tonight into Tuesday morning. We will see a gradual drying trend Tuesday afternoon into Tuesday night when a weak high pressure ridge moves overhead. By Wednesday afternoon the next system begins its move into the state. Weather Monday Monday Night Tuesday Temperature(°F) 10-15 -2-3 8-13 Wind Speed(mph) 10-20 6-16 G20 12-22 Wind Direction W N->NE N->W Sky Cover Overcast Overcast Mostly Cloudy Snow(in) 6-8 2-4 0 Snowpack Discussion One storm just rolls into the next around here. Skiers in the Fremont Pass area on Sunday remotely triggered a 2-3 foot deep slide from a very low angled slope several hundred feet away. This slide ran to the ground on a southerly slope near treeline and left around 10 feet of debris in a nasty terrain trap/gully. The skiers also reported big rumbling collapses and shooting cracks indicating a very tender snowpack. With plenty of new snow and moderate to strong ridge top winds, we are expecting another natural avalanche cycle. We have two main avalanche concerns: one lies in the upper snowpack, the other is the possibility of deep slab releases. New snow may slide on a variety of weak layers including buried facets, lower density snow that fell earlier in the week, or hard slabs from our last major wind storm. As evidenced by the triggered slide on Sunday, the chance of full-depth slides exists as well. An avalanche initiated higher in the snowpack has the potential to step down into the weaker snow underneath. The avalanche danger will continue to rise as snow accumulates. Avoid traveling on or below steep slopes at this time. Avalanche Danger With plenty of snow available for wind transport, ample incoming snow and strong southwest winds, we have raise the avalanche danger to HIGH on north, northeast, east, southeast and south slopes in near and above treeline areas. It is CONSIDERABLE otherwise. Unstable slabs and human-triggered avalanches are likely to probable on steep slopes. You may find unstable windslabs on steep slopes, even below treeline in open areas. [57]Please let us know if you see any avalanche activity or experienced signs of instability. Your observations are very important to us! Steamboat ========= Current Keywords: CONSIDERABLE, avalanche danger, crust, high pressure, human triggered, low pressure, path, stress, trough, Mountain Weather and Avalanche Forecast for the Steamboat and Parks Range Zone Forecast Issued on 2/4/2008 4:21:06 PM Forecaster: Scott Toepfer Weather Synopsis The current low pressure trough will cross Colorado tonight on its slow trek eastward. First, a strong impulse of moisture moving NE from New Mexico/Arizona will move into the San Juans and Sangre De Cristos with more snow, but at least winds have shown sign of decreasing as the trough gradually moves east. This stream of moisture will also track up along the east side of the Front Ranges tonight into Tuesday morning. With the shift to northerly winds the focus of snowfall will move into the north and central zones and north side of the San Juan later tonight into Tuesday morning. We will see a gradual drying trend Tuesday afternoon into Tuesday night when a weak high pressure ridge moves overhead. By Wednesday afternoon the next system begins its move into the state. Weather Monday Night Tuesday Tuesday Night Temperature(°F) 0-5 11-16 -1-4 Wind Speed(mph) 3-13 7-17 14-24 Wind Direction N WNW W Sky Cover Overcast Mostly Cloudy Mostly Cloudy Snow(in) 3-5 0-2 0-2 Snowpack Discussion Limited visibility and limited observations are what we have to work with today. One observation from the weekend pointed to poor bonding of recent storm snow to underlying slightly older snow surface. Another one plus feet of new snow from the Steamboat zone as of this morning reported from observers, and there was also some light blowing snow noted. There has been significant new snow over the last few days, (weeks). Eventually we reach critical mass and stress of new snow overwhelms strengths in the inclined snowpack. Most all of the recent activity has been on terrain of 35 degrees and steeper, but there have been a few reports of lower angle terrain producing slides filtering in, triggered by humans from long distances away. A sign that the snowpack is under a lot of stress. The avalanche danger has been at CONSIDERABLE for some time, and with good reason. Savy backcountry travelers will be able to move safely across the backcountry, just dont become complacent because there are tracks or you have ridden a particular path this year. It is an active avalanche year. Sadly, Colorado's fifth avalanche fatality occurred Friday in the southwestern Flat Tops. A snowmobiler triggered an avalanche on a steep slope, 2 feet deep, 400 feet wide and running 350 feet downhill. The slide is classified as a SS-AM-R4D2-O, running on a buried sun crust. CAIC forecasters went to the accident site Saturday. We will report details as they become available. Click here for the [57]preliminary report. Avalanche Danger The avalanche danger in the Steamboat Zone is CONSIDERABLE on all aspects and elevations. Human triggered slides are possible to probable today. If you have any observations or data to share, please send them to [58]caic@qwest.net. Vail ==== Current Keywords: CONSIDERABLE, MODERATE, avalanche danger, cornices, high pressure, human triggered avalanches, low pressure, slab, slabs, stress, trough, wind loading, windslabs, Mountain Weather and Avalanche Forecast for the Vail and Summit County Zone Forecast Issued on 2/4/2008 6:03:35 AM Forecaster: Scott Toepfer Weather Synopsis The current low pressure trough will cross Colorado tonight on its slow trek eastward. First, a strong impulse of moisture moving NE from New Mexico/Arizona will move into the San Juans and Sangre De Cristos with more snow, but at least winds have shown sign of decreasing as the trough gradually moves east. This stream of moisture will also track up along the east side of the Front Ranges tonight into Tuesday morning. With the shift to northerly winds the focus of snowfall will move into the north and central zones and north side of the San Juan later tonight into Tuesday morning. We will see a gradual drying trend Tuesday afternoon into Tuesday night when a weak high pressure ridge moves overhead. By Wednesday afternoon the next system begins its move into the state. Weather Monday Monday Night Tuesday Temperature(°F) 12-17 -2 to 3 4-9 Wind Speed(mph) 5-15 G20s 5-15 G20s 10-20 G30s Wind Direction W N WNW Sky Cover Overcast Overcast Mostly Cloudy Snow(in) 2-4 1-3 Tr-2 Snowpack Discussion New snow over the past several days has added up to about a foot and a half in many areas around the Vail/Summit Zone. Another 2-5 inches on Sunday night. Relatively slow loading over the past several days has been a generally good thing, not stressing the snowpack too much at one time. However, westerly winds have redistributed snow onto north through east through south aspects, especially near and above treeline. Recent activity in the Ten-Mile, Gore and Vail Pass areas could be directly linked to heavy wind loading. Winds will become more north to north east next 12 hours, and decrease. This will also slow fresh slab development. We continue to get reports of collpase and cracking, tender and reactive cornices, and fresh slide activity. Most of this has been on the eastern half have of the compass, N-E-S aspects. Near and above treeline have been the most active, but there has been much snow well below treeline too, so do not drop your guard much even when getting low off ridgelines. This also tells that avalanche tracks have a lot of snow, quite deep. A good storm cycle could bring on some big, long running slides. Remember that new snow may disguise older hard slabs, so dig down and analyze the snowpack stratigraphy before committing to steeper terrain. More snow and wind is in the forecast through Monday, so the avalanche danger will not subside. Avalanche Danger The avalanche danger in the Vail-Summit Zone is CONSIDERABLE on north, northeast, east, southeast, and south aspects near and above treeline. Human triggered avalanches are probable on steep slopes. The avalanche danger is MODERATE on other aspects above treeline and on all slopes below treeline. You may find unstable windslabs on steep slopes, even below treeline in open areas.