Aspen ===== Current Keywords: CONSIDERABLE, MODERATE, avalanche danger, crusts, faceted, high pressure, low pressure, powder. , settle, slab, sugary, trough, weak layers, wind slab, wind slabs, Mountain Weather and Avalanche Forecast for the Aspen Zone Forecast Issued on 1/24/2008 4:24:10 PM Forecaster: John Snook Weather Synopsis Moist southwest flow wrapping around a low pressure system off the California coast has been dumping snow on the southern San Juan Mountains during Thursday. Winds will veer to westerly overnight changing the focus of snowfall after midnight to west aspects of the northern San Juan, central, and northern mountains on Friday. Snow will linger across the northern mountains into Saturday morning. High pressure ridging will bring a break from the snow this weekend. The California low takes aim at southwest Colorado on Sunday afternoon. The system moves slowly across Colorado on Monday as a broad long wave trough of low pressure. This looks like a good snow producer for most mountain locations into early Tuesday. Weather Thursday Night Friday Friday Night Temperature(°F) 5-10 10-15 2-7 Wind Speed(mph) 15-25 G35 15-25 G35 15-25 Wind Direction WSW W W Sky Cover Overcast Overcast Mostly Cloudy Snow(in) 2-4 1-3 0 Snowpack Discussion Just as our snowpack is finally starting to settle and adjust to the weight of January's snow, we have a couple more storms forecasted to affect the state later today and early next week. Earlier this week, strong winds added another layer of wind slab to the top of our snowpack. More wind and some light snow in the forecast could add yet another layer of storm snow and wind slab on top of the existing hard and weak layers. Depending the aspect and elevation you travel on, you will find crusts, wind slabs, some "sugary" faceted snow, surface hoar, and some older powder. Some of these will make good weak layers as the snow adds up with the next couple storms. Keep an eye out for increasing avalanche activity through Friday. Soft slab slides breaking away from beneath the recent storm snow and wind slabs are a concern. We cannot have a snowpack discussion this winter without mentioning those persistent, deep weak layers. Although they are becoming difficult to trigger, avalanches do have the potential to step down and become large events. The structure of the snowpack right now inspires VERY LITTLE confidence for bigger terrain in most areas of the Aspen Zone. A stronger layer in the middle of the snowpack may give you a false sense of security but remember that our snow cover in Colorado is highly variable. Find an area where that midpack is thinner and you may find yourself going for an unplanned ride. Avalanches in these conditions are often triggered from lower on the slope where the snowpack thins out and puts you closer to those weak layers. You need to choose your terrain wisely. Good route finding and the ability to select terrain that is appropriate for the current conditions are two great tools to take with you into the backcountry this season. There is a lot of great riding out there now, but the snowpack demands a lot of respect. Consider the consequences of a wrong decision. Avalanche Danger With snow and wind in the forecast, we will hold the danger at CONSIDERABLE on north, northeast, east, and southeast aspects near and above treeline. The avalanche danger on all other aspects near and above treeline and all slopes below treeline is MODERATE. 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 out there today. Front Range =========== Current Keywords: CONSIDERABLE, MODERATE, avalanche danger, collapsing , crust, high pressure, human triggered, human triggered avalanches, low pressure, natural, path, shears, slab, slabs, trough, weak layers, whumpfing, wind slab, wind slabs, Mountain Weather and Avalanche Forecast for the Front Range Zone Forecast Issued on 1/24/2008 4:23:37 PM Forecaster: John Snook Weather Synopsis Moist southwest flow wrapping around a low pressure system off the California coast has been dumping snow on the southern San Juan Mountains during Thursday. Winds will veer to westerly overnight changing the focus of snowfall after midnight to west aspects of the northern San Juan, central, and northern mountains on Friday. Snow will linger across the northern mountains into Saturday morning. High pressure ridging will bring a break from the snow this weekend. The California low takes aim at southwest Colorado on Sunday afternoon. The system moves slowly across Colorado on Monday as a broad long wave trough of low pressure. This looks like a good snow producer for most mountain locations into early Tuesday. Weather Thursday Night Friday Friday Night Temperature(°F) 7-12 13-18 5-10 Wind Speed(mph) 15-25 G45 15-25 G55 15-25 G45 Wind Direction WSW W W Sky Cover Overcast Overcast Mostly Cloudy Snow(in) 0-2 1-3 0-1 Snowpack Discussion Avalanche mitigation work in the Stanley slide path was unable to produce any results. An observer near Stanley on Thursday found several new layers including soft slabs and a thin hard crust on top of the hard over weak layers observed earlier this week. Instability tests indicated some easy shears, but no collapsing or whumpfing was observed in the area. The last reported slide was on Tuesday in Zero Creek, SE aspect starting at 11,700 feet natural hard slab. More wind and some light snow in the forecast could add yet another layer of storm snow and wind slab on top of the existing hard and weak layers. Human triggered slides breaking away from beneath the recent storm snow and wind slabs are possible to probable. Recent weather conditions including cold temperatures and periods of strong winds have done little to change the concern for deep slab instabilities. If a small upper snowpack slide is triggered it could break down into the weaker basal layers creating a large avalanche. Finding a thin spot in the hard slab may also trigger a large slide. These are common near rock outcroppings, downed timber and below cliff bands. Be particularly aware of potential consequences. Avoid steep slopes that could carry you over cliff bands or into trees. Choose your terrain wisely by knowing where you are, measuring slope angles and having your escape routes planned. 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, cornices, high pressure, human triggered, human triggered avalanches, low pressure, sluffing, trough, wind slab, wind slabs, wind-loaded, Mountain Weather and Avalanche Forecast for the Grand Mesa Zone Forecast Issued on 1/24/2008 4:24:38 PM Forecaster: John Snook Weather Synopsis Moist southwest flow wrapping around a low pressure system off the California coast has been dumping snow on the southern San Juan Mountains during Thursday. Winds will veer to westerly overnight changing the focus of snowfall after midnight to west aspects of the northern San Juan, central, and northern mountains on Friday. Snow will linger across the northern mountains into Saturday morning. High pressure ridging will bring a break from the snow this weekend. The California low takes aim at southwest Colorado on Sunday afternoon. The system moves slowly across Colorado on Monday as a broad long wave trough of low pressure. This looks like a good snow producer for most mountain locations into early Tuesday. Weather Thursday Night Friday Friday Night Temperature(°F) 12-17 17-22 10-15 Wind Speed(mph) 15-25 10-20 5-15 Wind Direction SW WSW SW Sky Cover Overcast Overcast Partly Cloudy Snow(in) 1-3 1-3 0 Snowpack Discussion Storm snow and wind from earlier in the week have created wind slabs and cornices at higher elevations of the Grand Mesa. During this time, observers noted some minor sluffing and small slides resulting from the upper wind slab layer breaking away. The forecast is for light to moderate snow and some wind from the southwest and then west. This will generate another layer of storm snow and fresh wind slabs on exposed slopes. Human triggered slides within the upper portions of the snowpack remain possible on these slopes. 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. You should watch for changing conditions on Friday as this next storm system moves through. 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, high pressure, lee , low pressure, slabs, trough, wind slabs, Mountain Weather and Avalanche Forecast for the Northern San Juan Mountain Zone Forecast Issued on 1/24/2008 4:25:09 PM Forecaster: John Snook Weather Synopsis Moist southwest flow wrapping around a low pressure system off the California coast has been dumping snow on the southern San Juan Mountains during Thursday. Winds will veer to westerly overnight changing the focus of snowfall after midnight to west aspects of the northern San Juan, central, and northern mountains on Friday. Snow will linger across the northern mountains into Saturday morning. High pressure ridging will bring a break from the snow this weekend. The California low takes aim at southwest Colorado on Sunday afternoon. The system moves slowly across Colorado on Monday as a broad long wave trough of low pressure. This looks like a good snow producer for most mountain locations into early Tuesday. Weather Thursday Night Friday Friday Night Temperature(°F) 5-10 12-17 2-7 Wind Speed(mph) 15-25 G35 10-20 5-15 Wind Direction SW WSW SW Sky Cover Overcast Mostly Cloudy Partly Cloudy Snow(in) 4-6 0-2 0 Snowpack Discussion The latest storm system has moved into the San Juan Mountains on Tuesday. As of Tuesday afternoon, more snowfall has been observed south of Red Mountain Pass. Winds are expected to veer from southwest to west which will shift the focus of snowfall to the west and north of Red Mountain Pass. Ridgetop winds have been strong enough to move snow to lee and cross loaded aspects. While many areas above treeline have been scoured over the past several days, there is still been plenty of snow up high to be transported. Fresh slabs have been developing since early Thursday morning, loading on top of upper snowpack layers that proved to be reactive only a few days ago. High northerly slopes will be the most suspect today because of their orientation relative to the predominant wind flow, but remember that inter-basin winds have their own rules and loading can occur on any aspect. 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: CONSIDERABLE, avalanche danger, high pressure, human triggered, low pressure, natural, slab, trough, wind load, Mountain Weather and Avalanche Forecast for the Southern San Juan Mountain Zone Forecast Issued on 1/24/2008 4:25:27 PM Forecaster: John Snook Weather Synopsis Moist southwest flow wrapping around a low pressure system off the California coast has been dumping snow on the southern San Juan Mountains during Thursday. Winds will veer to westerly overnight changing the focus of snowfall after midnight to west aspects of the northern San Juan, central, and northern mountains on Friday. Snow will linger across the northern mountains into Saturday morning. High pressure ridging will bring a break from the snow this weekend. The California low takes aim at southwest Colorado on Sunday afternoon. The system moves slowly across Colorado on Monday as a broad long wave trough of low pressure. This looks like a good snow producer for most mountain locations into early Tuesday. Weather Thursday Night Friday Friday Night Temperature(°F) 10-15 15-20 7-12 Wind Speed(mph) 15-25 10-20 5-15 Wind Direction SW SW SW Sky Cover Overcast Mostly Cloudy Partly Cloudy Snow(in) 6-8 0-2 0 Snowpack Discussion The latest storm system has moved into the southern San Juan Mountains on Thursday. As of Thursday afternoon, about 9" of new snow was reported near Wolf Creek Pass. Wind speeds were initially on the light side, but are strengthening enough from the southwest to move snow around. Small natural slides are starting to occur, and some cracking within the new snow layer has been noted. With another 6-8" of snow in the forecast, I am raising the avalanche danger to overall CONSIDERABLE. You need to evaluate how well the new snow and wind load are bonding to the old snow surface. Consider the consequences should even a small slide develop. Do not let powder fever influence your decision making. You may need to dial it back to lower angle terrain for the next few days as this storm cycle plays out. Human triggered soft slab slides are probable and natural slides are possible on all steep slopes. Avalanche Danger The avalanche danger for the southern San Juan zone is overall CONSIDERABLE. Fresh snowfall will make human triggered soft slab slides probable and natural slides possible on all steep slopes. Sangre de Christo ================= Current Keywords: CONSIDERABLE, MODERATE, avalanche danger, cross loaded, high pressure, human triggered, lee , low pressure, slab, slabs, trough, wind loaded, wind slabs, Mountain Weather and Avalanche Forecast for the Sangre De Cristo Zone Forecast Issued on 1/24/2008 4:25:41 PM Forecaster: John Snook Weather Synopsis Moist southwest flow wrapping around a low pressure system off the California coast has been dumping snow on the southern San Juan Mountains during Thursday. Winds will veer to westerly overnight changing the focus of snowfall after midnight to west aspects of the northern San Juan, central, and northern mountains on Friday. Snow will linger across the northern mountains into Saturday morning. High pressure ridging will bring a break from the snow this weekend. The California low takes aim at southwest Colorado on Sunday afternoon. The system moves slowly across Colorado on Monday as a broad long wave trough of low pressure. This looks like a good snow producer for most mountain locations into early Tuesday. Weather Thursday Night Friday Friday Night Temperature(°F) 10-15 17-22 7-12 Wind Speed(mph) 15-25 G40 15-25 G40 15-25 Wind Direction SW WSW WSW Sky Cover Overcast Partly Cloudy Partly Cloudy Snow(in) 1-3 0 0 Snowpack Discussion Our last observation from the Colorado Sangres nearly two weeks ago noted plenty of hard slabs to be found. These were primarily on the lee aspects due to persistent northerly winds, but could be found on cross loaded terrain features like gullies as well. The Sangres have a relatively shallow snowpack. The primary concern in neighboring zones with shallow snowpacks is localized deep slab instabilities. The stiff wind slabs will hold your weight in many areas, but you can breakthrough 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. Think of the consequences of a big ride during your route selection process. As always, we really like to get observations, even if it is just cloud cover and new snow from the valley floors. 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, cross loaded, cross-loaded, front, high pressure, human triggered, low pressure, natural, powder , slab, slabby, trough, weak layers, wind loaded, wind slabs, Mountain Weather and Avalanche Forecast for the Sawatch Range Zone Forecast Issued on 1/24/2008 4:25:56 PM Forecaster: John Snook Weather Synopsis Moist southwest flow wrapping around a low pressure system off the California coast has been dumping snow on the southern San Juan Mountains during Thursday. Winds will veer to westerly overnight changing the focus of snowfall after midnight to west aspects of the northern San Juan, central, and northern mountains on Friday. Snow will linger across the northern mountains into Saturday morning. High pressure ridging will bring a break from the snow this weekend. The California low takes aim at southwest Colorado on Sunday afternoon. The system moves slowly across Colorado on Monday as a broad long wave trough of low pressure. This looks like a good snow producer for most mountain locations into early Tuesday. Weather Thursday Night Friday Friday Night Temperature(°F) 8-13 10-15 7-12 Wind Speed(mph) 15-25 15-25 G40 15-25 G40 Wind Direction WSW W W Sky Cover Overcast Overcast Partly Cloudy Snow(in) 2-4 0-2 0 Snowpack Discussion Avalanche activity has really slowed over the last few days but has not stopped. The most recent reported slide occurred last weekend. It was 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. South of St Elmo, several large slides had been reported, mostly on N-E aspects. One quite large slide ran off a cross loaded west aspect and crossed the road which has not happened in many years. With the continued cold temperatures, a general weakening of the old snow will continue. Any new snow, and wind deposited snow will have weak layers to rest on. We are anticipating the complex snowpack structure will result in variable unstable layers for well into the spring. The forecast is for several inches of new snow along with strong winds. This will put another layer of slabby snow on top of a collection of older wind slabs and persistently weak layers. Human triggered slides where you break away the upper layer will be possible to probable on steep slopes. Localized deep slab instabilities are still lurking. These are here to stay and should be on the forefront of your decision making process. If you trigger a smaller slide, it could step down into the snowpack to create a larger avalanche. Finding a thin spot in the hard slab may also trigger a large slide. These are common near rock outcroppings, downed timber, and below cliff bands. Be particularly aware of potential consequences. Avoid steep slopes that could carry you over cliff bands or into trees. There is good riding to be found. But choose your terrain wisely by knowing where you are, measuring slope angles and having your escape routes planned. If new snow and wind comes into the zone, temper your powder fever. It is hard to do this but give the snowpack time to adjust to the new load before diving in. Stick to slopes less than 34 degrees for a few days and evaluate each slope individually. 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. 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, cross loaded, high pressure, lee , low pressure, slab, trough, wind slabs, Mountain Weather and Avalanche Forecast for the Steamboat and Parks Range Zone Forecast Issued on 1/24/2008 4:23:21 PM Forecaster: John Snook Weather Synopsis Moist southwest flow wrapping around a low pressure system off the California coast has been dumping snow on the southern San Juan Mountains during Thursday. Winds will veer to westerly overnight changing the focus of snowfall after midnight to west aspects of the northern San Juan, central, and northern mountains on Friday. Snow will linger across the northern mountains into Saturday morning. High pressure ridging will bring a break from the snow this weekend. The California low takes aim at southwest Colorado on Sunday afternoon. The system moves slowly across Colorado on Monday as a broad long wave trough of low pressure. This looks like a good snow producer for most mountain locations into early Tuesday. Weather Thursday Night Friday Friday Night Temperature(°F) 10-15 15-20 7-12 Wind Speed(mph) 15-25 G35 15-25 G35 15-25 G35 Wind Direction WSW WSW WSW Sky Cover Overcast Overcast Overcast Snow(in) 1-3 3-5 0-2 Snowpack Discussion Steamboat area observers are noting that the lower snowpack is gaining strength. It is never a good idea in Colorado to totally ignore the possibility for deep slab instabilities which may be found where the snowpack is thinner, but our primary concerns are in the upper snowpack. Storm snow and wind from earlier in the week have created new wind slabs on exposed slopes. Several soft slab slides were reported since the beginning of the week, the most recent on Wednesday on NE-E-SE aspects in the Cornice Bowl south of Sand Mountain. The forecast is for more snow and moderate winds from the southwest and then west. Expect to find more soft wind slabs to develop on lee easterly aspects and cross loaded terrain features on north and south aspects. Slides breaking away from beneath the recent storm snow and wind slabs are the biggest problem. Even small slides can ruin your day if they carry into trees or over rocks. You need to consider these consequences before venturing out too far on steep terrain. Work your way up to steeper terrain and constantly watch for signs of instability such as recent slide activity. 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, MODERATE, avalanche danger, cross loaded, faceting, facets, high pressure, human triggered, human triggered avalanches, low pressure, natural, shears, shovel, slab, slabs, start zones, trough, weak layers, wind slab, wind slabs, Mountain Weather and Avalanche Forecast for the Vail and Summit County Zone Forecast Issued on 1/24/2008 4:23:52 PM Forecaster: John Snook Weather Synopsis Moist southwest flow wrapping around a low pressure system off the California coast has been dumping snow on the southern San Juan Mountains during Thursday. Winds will veer to westerly overnight changing the focus of snowfall after midnight to west aspects of the northern San Juan, central, and northern mountains on Friday. Snow will linger across the northern mountains into Saturday morning. High pressure ridging will bring a break from the snow this weekend. The California low takes aim at southwest Colorado on Sunday afternoon. The system moves slowly across Colorado on Monday as a broad long wave trough of low pressure. This looks like a good snow producer for most mountain locations into early Tuesday. Weather Thursday Night Friday Friday Night Temperature(°F) 5-10 10-15 2-7 Wind Speed(mph) 15-25 G35 15-25 G45 15-25 G40 Wind Direction WSW W W Sky Cover Overcast Overcast Overcast Snow(in) 1-3 0-2 0-1 Snowpack Discussion Avalanche activity has slowed over the last few days but still has not stopped. On Thursday, avalanche mitigation work near Vail Pass produced a number of small soft slabs on southwest through northwest facing aspects. The most recent backcountry activity, both human triggered and natural, occurred earlier in the week near Vail Pass. This activity started near or above treeline on east through south through southwest aspects. Our observer on Thursday above the north fork of the Swan River noted at least four slabs within the upper snowpack and lots of easy hand/shovel shears. More wind and some light snow in the forecast could add yet another layer of storm snow and wind slab on top of the existing hard and weak layers. Human triggered soft slab slides breaking away from beneath the recent storm snow and wind slabs are possible to probable. The Vail side of the zone seems to have a better chance for this upper snowpack activity. The recently formed slabs are sitting above weak surface facets. Surface layers in cross loaded start zones facing north, east and south have been quite reactive. The cold temperatures this month have really driven the surface faceting process making shallow slab stability poor. If you trigger one of these soft slabs, the probability of the fracture stepping down to deeper weak instabilities is of greater concern. Finding a thin spot in the hard slab may also trigger a large slide. These are common near rock outcroppings, downed timber and below cliff bands. Be particularly aware of potential consequences. Avoid steep slopes that could carry you over cliff bands or into trees. Choose your terrain wisely by knowing where you are, measuring slope angles and having your escape routes planned. The name of the game with our current snowpack is avoiding start zones steeper than 34 degrees as well as terrain features that terminate in a creek bottom. Observers are noting that above treeline northwest aspects are getting filled with snow again. I am tweaking the avalanche danger upward in these areas. 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, south, and southwest aspects near and above treeline. Human triggered avalanches are probable in these areas. Elsewhere the danger is MODERATE.