Aspen ===== Current Keywords: CONSIDERABLE, MODERATE, avalanche danger, faceted, facets, human triggered avalanches, powder , settle, slab, trough, windslabs, Mountain Weather and Avalanche Forecast for the Aspen Zone Forecast Issued on 12/4/2007 7:09:30 AM Forecaster: John Snook Weather Synopsis The Great Basin ridge is slowly breaking down opening the door for a series of short waves to cross the state in west-northwest flow. The first, relatively weak, wave arrives this evening providing a couple of inches of snow by morning for the mountains north of I-70, and lighter amounts for the central mountains. Ridge top winds will continue to be strong especially over and east of the Continental Divide. The jet stream sags further south on Wednesday creating a chance for snow over the San Juan. The next more potent wave arrives Wednesday evening. Snowfall is expected for most mountain locations with up to a foot expected by mid-day Thursday over favored west-facing aspects. A deep long-wave trough is expected to dig south along the West Coast by this weekend. Winds will shift to the southwest and shift the focus for snowfall to the southwest mountains. Temperatures will be warm again, but higher elevations of the San Juan could be looking at another significant storm for the weekend. A preliminary report of the [59]Hot Dog Bowl Accident near Cameron Pass is now available on-line. Weather Tuesday Tuesday Night Wednesday Temperature(°F) 35-40 22-27 30-35 Wind Speed(mph) 15-25 G40 10-20 G30 15-25 Wind Direction WNW WNW W Sky Cover Mostly Clear Mostly Cloudy Mostly Cloudy Snow(in) 0 0-1 0-1 Snowpack Discussion Natural avalanching has slowed down as storm instabilities settle out. Now the problem is a strengthening slab sitting on the pockets of weak facets formed earlier in the season. Southwest winds transported the 2-3 feet of storm snow onto northeasterly aspects during the storm. Since the storm, winds have veered to west and then northwest, loading east and southeasterly slopes. Near and above treeline the winds built fresh windslabs on weak, faceted snow from earlier in the season. You will find the combination of weak facets and new windslabs on slopes facing northwest, through northeast, through east. Look for cross loading of ridges gullies and other terrain features as well. Human triggered avalanches are probable today, especially on steep northwest, north, northeast, and east facing slopes near and above treeline. Given the weak nature of the old snowpack on these aspects, large avalanches are possible. Do not let the nice weather and draw of fresh powder draw you into making bad a bad decision. Be careful out there! 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 [60]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 are probable on steep slopes today. On other aspects and below treeline the danger is MODERATE. Your backcountry observations are very important to us. Observations can be submitted to [61]caic@qwest.net . Front Range =========== Current Keywords: CONSIDERABLE, MODERATE, avalanche danger, drift, drifting, human triggered avalanches, natural, natural avalanche, slab, slabs, trough, whumpfing, windloaded, Mountain Weather and Avalanche Forecast for the Front Range Zone Forecast Issued on 12/4/2007 6:03:44 AM Forecaster: John Snook Weather Synopsis The Great Basin ridge is slowly breaking down opening the door for a series of short waves to cross the state in west-northwest flow. The first, relatively weak, wave arrives this evening providing a couple of inches of snow by morning for the mountains north of I-70, and lighter amounts for the central mountains. Ridge top winds will continue to be strong especially over and east of the Continental Divide. The jet stream sags further south on Wednesday creating a chance for snow over the San Juan. The next more potent wave arrives Wednesday evening. Snowfall is expected for most mountain locations with up to a foot expected by mid-day Thursday over favored west-facing aspects. A deep long-wave trough is expected to dig south along the West Coast by this weekend. Winds will shift to the southwest and shift the focus for snowfall to the southwest mountains. Temperatures will be warm again, but higher elevations of the San Juan could be looking at another significant storm for the weekend. A preliminary report of the [59]Hot Dog Bowl Accident near Cameron Pass is now available on-line. Weather Tuesday Night Wednesday Wednesday Night Temperature(°F) 35-40 23-28 30-35 Wind Speed(mph) 15-25 G45 15-25 G50 15-25 G40 Wind Direction WNW WNW W Sky Cover Increasing Overcast Mostly Cloudy Snow(in) 0 0-2 0-1 Snowpack Discussion It is getting harder to trigger avalanches below treeline. Above treeline, though, slopes are still loading. Strong northwest winds continued to blow and drift snow into Tuesday morning. The continued loading of a weak snowpack remains a problem. Avalanche activity did slow down on Monday, but observers reported two significant avalanches. The largest occurred in the Ten Mile Range, where an 8 foot deep, 1500 foot wide natural avalanche ran Sunday night. A smaller natural avalanche ran Monday afternoon near Loveland Pass. Winds were strong, and drifting large amounts of snow, over both the Front Range and Vail-Summit zones. Over the weekend, observers reported avalanches and signs of instability on most aspects. There was lots of cracking, whumpfing, and avalanches were very easy to trigger. Most were small, but ran to the ground. Sizable natural avalanches ran from heavily windloaded north, northeast, east, and southeast aspects above treeline. The tender old snow has not gone away. Now it is topped by a stiffer, harder slab. Avalanches will be a little harder to trigger, but run larger. You will find unstable slabs on steep slopes near and above treeline. The old snow underneath is quite weak. As the slabs strengthen, avalanches can propagate further and run larger. Winter is back, with full hard slab conditions. Clean up your rusty skills, sharpen your avalanche eyeballs, and travel very cautiously out there. An accident report from the Hot Dog Bowl incident will be posted soon on the web site. Avalanche Danger The avalanche danger is CONSIDERABLE on NW-N-NE-E-SE aspects near and above treeline. Human triggered avalanches are probable today. The avalanche danger is MODERATE on other aspects and below treeline. Grand Mesa ========== Current Keywords: LOW, MODERATE, avalanche danger, dense, precipitation , settle, trough, Mountain Weather and Avalanche Forecast for the Grand Mesa Zone Forecast Issued on 12/4/2007 6:06:02 AM Forecaster: John Snook Weather Synopsis The Great Basin ridge is slowly breaking down opening the door for a series of short waves to cross the state in west-northwest flow. The first, relatively weak, wave arrives this evening providing a couple of inches of snow by morning for the mountains north of I-70, and lighter amounts for the central mountains. Ridge top winds will continue to be strong especially over and east of the Continental Divide. The jet stream sags further south on Wednesday creating a chance for snow over the San Juan. The next more potent wave arrives Wednesday evening. Snowfall is expected for most mountain locations with up to a foot expected by mid-day Thursday over favored west-facing aspects. A deep long-wave trough is expected to dig south along the West Coast by this weekend. Winds will shift to the southwest and shift the focus for snowfall to the southwest mountains. Temperatures will be warm again, but higher elevations of the San Juan could be looking at another significant storm for the weekend. A preliminary report of the [59]Hot Dog Bowl Accident near Cameron Pass is now available on-line. Weather Tuesday Tuesday Night Wednesday Temperature(°F) 43-48 27-32 40-45 Wind Speed(mph) 5-15 0-10 5-15 Wind Direction NW WNW WSW Sky Cover Partly Cloudy Mostly Cloudy Mostly Cloudy Snow(in) 0 0-1 0 Snowpack Discussion Storm totals from the weekend on the Grand Mesa were in the 20-25 inch range. Below around 9500 feet much of the precipitation was rain. Above the snowline, the storm snow was probably quite dense, as it had high water content and the temperatures were quite warm. This will help new snow to settle and bond. The avalanche danger is low where new snow fell on bare ground. However, shady aspects that 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 north, northeast, or east aspect. 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. Avalanche Danger The avalanche danger is MODERATE on steep N-NE-E slopes at the higher elevations, where there are pockets of old snow. The danger is LOW on other aspects. Watch for loose avalanches on steep, sunny slopes. San Juan North ============== Current Keywords: CONSIDERABLE, MODERATE, collapsing , facets, human triggered avalanches, natural, powder , settles, settling, slab, slabs, trough, whumphing, wind slab, Mountain Weather and Avalanche Forecast for the Northern San Juan Mountain Zone Forecast Issued on 12/4/2007 6:06:37 AM Forecaster: John Snook Weather Synopsis The Great Basin ridge is slowly breaking down opening the door for a series of short waves to cross the state in west-northwest flow. The first, relatively weak, wave arrives this evening providing a couple of inches of snow by morning for the mountains north of I-70, and lighter amounts for the central mountains. Ridge top winds will continue to be strong especially over and east of the Continental Divide. The jet stream sags further south on Wednesday creating a chance for snow over the San Juan. The next more potent wave arrives Wednesday evening. Snowfall is expected for most mountain locations with up to a foot expected by mid-day Thursday over favored west-facing aspects. A deep long-wave trough is expected to dig south along the West Coast by this weekend. Winds will shift to the southwest and shift the focus for snowfall to the southwest mountains. Temperatures will be warm again, but higher elevations of the San Juan could be looking at another significant storm for the weekend. A preliminary report of the [59]Hot Dog Bowl Accident near Cameron Pass is now available on-line. Weather Tuesday Tuesday Night Wednesday Temperature(°F) 37-42 24-29 32-37 Wind Speed(mph) 10-20 10-20 12-22 Wind Direction N NW WNW Sky Cover Mostly Clear Mostly Cloudy Overcast Snow(in) 0 0-1 0-2 Snowpack Discussion The weekend snow is settling quickly and becoming more cohesive. This is positive where the snow fell on bare ground. It is turning into a good base. The problem areas are the slopes that had old snow prior to the storm. All those old, weak facets are now topped by a strengthening slab. Natural activity has tapered off as the slab settles. Human triggered avalanches are still possible. Stronger slabs can lure you onto steeper and more exposed slopes, then fracture fairly large. The weekend storm quickly returned us to a common Colorado snowpack problem. Winds were southwesterly, then westerly, finally swinging to the northwest after the storm cleared. With plenty of snow to transport, particularly from northerly slopes, you can find wind slab on most aspects of open slopes. Continued high wind speeds can load slopes well below ridgeline elevations and affect the snow surface below treeline. Numerous natural and triggered avalanches were reported over the weekend. The majority of the observed activity occurred on northwest, north, and northeast aspects near and above treeline. Those same slopes had the weakest old snow layers underneath the storm snow. Observers also reported activity on east and southeast aspects, and a few slides below treeline. Most of the avalanches ran down to the old snow or the ground, three to five feet deep and up to several hundred feet wide. Backcountry observers noted all the classic signs of instability including cracking, collapsing and whumphing this weekend. This is a time to be very cautious - do not jump into a slope just because you are powder starved! Use sound decision making when traveling in the backcountry and consider the consequences of being caught in even a small slide. Avalanche Danger The danger is CONSIDERABLE on NW-N-NE aspects at all elevations. On E-SE aspects, the danger is CONSIDERABLE near and above treeline, and MODERATE below treeline. On S-SW-W aspects, the danger is MODERATE. The stability is improving, but unstable slabs are still San Juan South ============== Current Keywords: LOW, MODERATE, avalanche danger, crusts, dense, facets, powder, , settle, slabs, surface hoar, trough, weak layers, windloaded, Mountain Weather and Avalanche Forecast for the Southern San Juan Mountain Zone Forecast Issued on 12/4/2007 6:09:54 AM Forecaster: John Snook Weather Synopsis The Great Basin ridge is slowly breaking down opening the door for a series of short waves to cross the state in west-northwest flow. The first, relatively weak, wave arrives this evening providing a couple of inches of snow by morning for the mountains north of I-70, and lighter amounts for the central mountains. Ridge top winds will continue to be strong especially over and east of the Continental Divide. The jet stream sags further south on Wednesday creating a chance for snow over the San Juan. The next more potent wave arrives Wednesday evening. Snowfall is expected for most mountain locations with up to a foot expected by mid-day Thursday over favored west-facing aspects. A deep long-wave trough is expected to dig south along the West Coast by this weekend. Winds will shift to the southwest and shift the focus for snowfall to the southwest mountains. Temperatures will be warm again, but higher elevations of the San Juan could be looking at another significant storm for the weekend. A preliminary report of the [59]Hot Dog Bowl Accident near Cameron Pass is now available on-line. Weather Tuesday Tuesday Night Wednesday Temperature(°F) 42-47 30-35 35-40 Wind Speed(mph) 10-20 0-10 5-15 Wind Direction NNW NW WSW Sky Cover Clear Mostly Cloudy Mostly Cloudy Snow(in) 0 0 0 Snowpack Discussion The Southern San Juans received almost 4 feet of snow from the weekend storm. Conditions went from dry to wintery in two days. The inital snow came in warm and dense. Temperatures dropped during the storm resulting in lighter snow on top. As storm-snow instabilites settle out, the snowpack turns into a good base under powder, with little to form weak layers. You might be able to find pockets of weak, old facets with triggerable slabs on top. Do not jump blindly onto steep, north, northeast, or east facing slopes. Enjoy the good conditions while they last. Sun crusts are forming on the sunny slopes, and there is surface hoar on shady slopes. Those could turn into perfect weak layers for the next storm. 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. Sangre de Christo ================= Current Keywords: avalanche danger, consolidate, crossloading, drifts, sluffs, trough, windslabs, Mountain Weather and Avalanche Forecast for the Sangre De Cristo Zone Forecast Issued on 12/4/2007 6:10:23 AM Forecaster: John Snook Weather Synopsis The Great Basin ridge is slowly breaking down opening the door for a series of short waves to cross the state in west-northwest flow. The first, relatively weak, wave arrives this evening providing a couple of inches of snow by morning for the mountains north of I-70, and lighter amounts for the central mountains. Ridge top winds will continue to be strong especially over and east of the Continental Divide. The jet stream sags further south on Wednesday creating a chance for snow over the San Juan. The next more potent wave arrives Wednesday evening. Snowfall is expected for most mountain locations with up to a foot expected by mid-day Thursday over favored west-facing aspects. A deep long-wave trough is expected to dig south along the West Coast by this weekend. Winds will shift to the southwest and shift the focus for snowfall to the southwest mountains. Temperatures will be warm again, but higher elevations of the San Juan could be looking at another significant storm for the weekend. A preliminary report of the [59]Hot Dog Bowl Accident near Cameron Pass is now available on-line. Weather Tuesday Tuesday Night Wednesday Temperature(°F) 45-50 28-33 37-42 Wind Speed(mph) 10-20 10-20 12-22 Wind Direction WNW W WSW Sky Cover Mostly Cloudy Mostly Cloudy Mostly Cloudy Snow(in) 0 0 0 Snowpack Discussion The Sangre de Cristo range picked up over an inch of water during last weekend's storm. The new snow was quite wet and came in with warm temperatures. It will probably stick pretty well to the bare ground. However, areas where there was snow prior to the storm, namely high elevation north and easterly aspects, could be sensitive. There was quite a bit of wind with this event, so thick drifts and sensitive windslabs lurk in the high-elevations areas. Strong winds continued, so expect lots of crossloading. If you are traveling in the high country you will be able to move from relatively safe to quite dangerous slopes very easily. Watch for changes in slope angle and aspect as these elements greatly affect snow stability. In general, the avalanche danger will increase as you move up in elevation or onto steeper and/or shadier aspects. The most likely place to trigger an avalanche is on steep slopes that face northwest, north, northeast and east and are near and above treeline. Recent warm temperatures will consolidate the storm snow. Loose wet sluffs are possible on steep rocky southerly slopes. 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 [60]caic@qwest.net Sawatch ======= Current Keywords: CONSIDERABLE, MODERATE, cross loading, crossloaded, crusts, drifted, drifts, facets, slabs, trough, windloaded, windslabs, Mountain Weather and Avalanche Forecast for the Sawatch Range Zone Forecast Issued on 12/4/2007 6:28:29 AM Forecaster: Brad Sawtell Weather Synopsis The Great Basin ridge is slowly breaking down opening the door for a series of short waves to cross the state in west-northwest flow. The first, relatively weak, wave arrives this evening providing a couple of inches of snow by morning for the mountains north of I-70, and lighter amounts for the central mountains. Ridge top winds will continue to be strong especially over and east of the Continental Divide. The jet stream sags further south on Wednesday creating a chance for snow over the San Juan. The next more potent wave arrives Wednesday evening. Snowfall is expected for most mountain locations with up to a foot expected by mid-day Thursday over favored west-facing aspects. A deep long-wave trough is expected to dig south along the West Coast by this weekend. Winds will shift to the southwest and shift the focus for snowfall to the southwest mountains. Temperatures will be warm again, but higher elevations of the San Juan could be looking at another significant storm for the weekend. A preliminary report of the [59]Hot Dog Bowl Accident near Cameron Pass is now available on-line. Weather Tuesday Night Wednesday Wednesday Night Temperature(°F) 35-40 22-27 30-35 Wind Speed(mph) 10-20 G30 10-20 15-25 G40 Wind Direction WNW W W Sky Cover Increasing Mostly Cloudy Mostly Cloudy Snow(in) 0 0-1 0-1 Snowpack Discussion Since the last storm, strong southwest, west, and now northwest winds drifted and crossloaded snow into gullies and behind terrain features. Some of the drifts and new snow are sitting on older, weak snow. Coverage prior to the storm was thin and variable, with the old snow remaining in steep, northerly gullies and pockets. Facets and crusts make up the stratigraphy of old snow, which make for poor bonding with new snow. Expect to find sensitive slabs in the backcountry. An observer reported tender snow over the weekend, especially in the Northern part of the zone. Moderate to strong winds out of the southwest built fresh windslabs, especially near and above treeline. Expect that loading has occured on northerly aspects and cross loading on ridges, gullies and other terrain features. Additionally, expect that loading patterns have occured further down slopes. The most likely place to trigger an avalanche is on a steep, windloaded north, northeast, or east aspect near and above treeline, but expect some tender slabs on northwest and southeast aspects. Approach or ride slopes in question one at a time. 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 [60]send us observations if you are getting out. Steamboat ========= Current Keywords: LOW, MODERATE, avalanche danger, drifted, drifts, facets, trough, whumpfing, windslabs, Mountain Weather and Avalanche Forecast for the Steamboat and Parks Range Zone Forecast Issued on 12/4/2007 6:02:20 AM Forecaster: John Snook Weather Synopsis The Great Basin ridge is slowly breaking down opening the door for a series of short waves to cross the state in west-northwest flow. The first, relatively weak, wave arrives this evening providing a couple of inches of snow by morning for the mountains north of I-70, and lighter amounts for the central mountains. Ridge top winds will continue to be strong especially over and east of the Continental Divide. The jet stream sags further south on Wednesday creating a chance for snow over the San Juan. The next more potent wave arrives Wednesday evening. Snowfall is expected for most mountain locations with up to a foot expected by mid-day Thursday over favored west-facing aspects. A deep long-wave trough is expected to dig south along the West Coast by this weekend. Winds will shift to the southwest and shift the focus for snowfall to the southwest mountains. Temperatures will be warm again, but higher elevations of the San Juan could be looking at another significant storm for the weekend. A preliminary report of the [59]Hot Dog Bowl Accident near Cameron Pass is now available on-line. Weather Tuesday Night Wednesday Wednesday Night Temperature(°F) 35-40 25-30 30-35 Wind Speed(mph) 10-20 G30 10-20 10-20 G30 Wind Direction WNW WNW W Sky Cover Increasing Overcast Mostly Cloudy Snow(in) 0 0-2 0-1 Snowpack Discussion The Steamboat Zone picked up 10 to 20 inches of new snow from this past weekend's storm, with the Bison Lake SNOTEL topping out the numbers, and Zirkel SNOTEL two inches behind. The snow on the ground prior to this storm was quite weak. New snow with wind has created sensitive drifts on top of the weak basal layers. Observers noted a reactive snowpack on steep, high elevation, northerly aspects where windslabs perched atop rotten facets. The old snow was quite patchy, and the avalanche danger will follow this pattern today. Beware of drifted and loaded slopes, especially on NW-N-NE-E 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. 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, drift, drifting, human triggered avalanches, natural avalanche, natural avalanches, slab, slabs, trough, whumpfing, windloaded, Mountain Weather and Avalanche Forecast for the Vail and Summit County Zone Forecast Issued on 12/4/2007 6:16:44 AM Forecaster: Brad Sawtell Weather Synopsis The Great Basin ridge is slowly breaking down opening the door for a series of short waves to cross the state in west-northwest flow. The first, relatively weak, wave arrives this evening providing a couple of inches of snow by morning for the mountains north of I-70, and lighter amounts for the central mountains. Ridge top winds will continue to be strong especially over and east of the Continental Divide. The jet stream sags further south on Wednesday creating a chance for snow over the San Juan. The next more potent wave arrives Wednesday evening. Snowfall is expected for most mountain locations with up to a foot expected by mid-day Thursday over favored west-facing aspects. A deep long-wave trough is expected to dig south along the West Coast by this weekend. Winds will shift to the southwest and shift the focus for snowfall to the southwest mountains. Temperatures will be warm again, but higher elevations of the San Juan could be looking at another significant storm for the weekend. A preliminary report of the [59]Hot Dog Bowl Accident near Cameron Pass is now available on-line. Weather Tuesday Night Wednesday Wednesday Night Temperature(°F) 33-38 22-27 28-33 Wind Speed(mph) 15-25 G40 10-20 G30 15-25 G35 Wind Direction WNW WNW W Sky Cover Increasing Overcast Mostly Cloudy Snow(in) 0 0-2 0-1 Snowpack Discussion It is getting harder to trigger avalanches below treeline. Above treeline, though, slopes are still loading. Strong northwest winds continued to blow and drift snow through Tuesday morning. The moderate to strong winds have loaded slopes further down the slope than what would be expected. Instead of "top" loading, think of "bottom" loading. The continued loading of a weak snowpack remains a problem. Avalanche activity did slow down on Monday, but observers reported two significant avalanches. The largest occurred in the Ten Mile Range, where an 8 foot deep, 1500 foot wide natural avalanche ran Sunday night. A smaller natural avalanche ran Monday afternoon near Loveland Pass. Winds were strong, and drifting large amounts of snow. Over the weekend, observers reported avalanches and signs of instability on most aspects but the majority of them occured on North West through North through East and South East. There was lots of cracking, whumpfing, and avalanches were very easy to trigger. Most were small, but ran to the ground. Sizable natural avalanches ran from heavily windloaded north, northeast, east, and southeast aspects above treeline. The tender old snow has not gone away. Now it is topped by a stiffer, harder slab. Avalanches will be a little harder to trigger, but run larger. You will find unstable slabs on steep slopes near and above treeline. The old snow underneath is quite weak. As the slabs strengthen, avalanches can propagate further and run larger. Winter is back, with full hard slab conditions. Clean up your rusty skills, sharpen your avalanche eyeballs, and travel very cautiously out there. The most important habbit to have is riding one at a time. Avalanche Danger The avalanche danger is CONSIDERABLE on NW-N-NE-E-SE aspects near and above treeline. Human triggered avalanches are probable today. The avalanche danger is MODERATE on other aspects and below treeline.