MJ HALL / Livin’ & Ridin’ the Adventure : Colorado Avalanche Report / November 11, 2012 Snow Storm

Monday, November 12, 2012

Colorado Avalanche Report / November 11, 2012 Snow Storm

Backcountry Forecasts > Statewide Avalanche

Statewide Avalanche Conditions

Issued: 11/12/2012 5:02 AM by Scott Toepfer

Expires: 11/13/2012 12:00 PM

Highlights

The first major winter storm of the season hit Colorado on Friday and Saturday. Areas favored with snowfall from southwesterly flow did best from this storm. Wolf Creek Pass reported 19" of snow from the storm. Outside of Crested Butte 17" of snow from the storm, and along the Highway 550 corridor in the San Juans from 7.5" to 12.5" of snow was reported at historical snow stakes. Reports indicated significantly more wind drifted snow in wind loaded areas from all these areas. Strong winds accompanied the storm, and as you can expect, a number of avalanches were reported. We've received great observations today. You can use the Observations>Observation Reports>Weather Stations page to track the snowfall through the day at your favorite weather stations.
We all anticipated snowfall with this storm, and folks got out into avalanche terrain. It is easy to discount the avalanche potential when there is just a few feet of drifted snow, with grass and flower stalks poking through. Do not get lulled into a sense of complacency. It is time to start thinking about avalanches. Is your avalanche rescue gear ready, and is your brain ready? Some early season reminders from Montana, and in Colorado: Jones Pass, Mt Baldy.
If you're out there exploring the early season snowpack, please let us know what you are seeing.

Weather Discussion

The recent storm is moving east and is followed by much colder air. Winds have drifted significant snow into avalanche starting zones. With the cold temperatures expected, instabilities will linger for some time. There are only some weak weather disturbances expected for the early part of the coming week, with little new snow expected until later this coming week. Cold temperatures will slowly ease, but at this time of year, cold equals sugar snow development.

Stay tuned to CAIC Weather Forecasts that are updated twice daily. Computer Model Forecasts are updated continuously. If you are going into the Colorado high country use our Weather Stations by Zone page to check current conditions.

Snowpack & Avalanche Discussion

Avalanche season is upon us. If you haven't been thinking about avalanches and terrain consequences you should now. The first major winter storm of the season arrived Friday and Saturday. Dense snowfall and strong winds "shellacked" the high country of the San Juan Mountains, Elk Range, Grand Mesa and the Rabbit Ears Pass area. Human triggered avalanches were reported in the Red Mountain Pass area outside Silverton, from the Elk Range outside Crested Butte, and the west side of the Vail/Summit County zone. Most of these slides were not large, but some were big enough to produce serious injury if not worse.

The recent storm was a good snow producer for many areas. The old snow underneath the new storm snow has had plenty of chances to weaken. Even though valley floor temperatures have seemed warm, nights are long, temperatures have dropped well below freezing, and the old snow has become quite weak. In some cases a melt freeze crust has formed at the old snow surface. These are all bad things, and could haunt us well into the coming winter.

It is not unusual for avalanche incidents and fatalities to make headlines in our state long before most of us are thinking about the consequences of an early season encounter. Avalanche accidents have occurred in Colorado every month of the year. Avalanches in the early season are less frequent than in mid-winter, but they are possible once snow begins to accumulate. This means that you need to start thinking avalanche again as fall snows begin to accumulate. As the first significant winter storm rolls past Colorado, make sure your gear and your brain are ready. Replace the batteries in your beacon.

The CAIC has begun to monitor the 2012-2013 snowpack. It should come as no surprise that once snow begins to accumulate, avalanches, both natural and triggered, can be expected. It is common for us to see reports of people caught in November avalanches every year. An early season encounter with an avalanche will often come with a ride through rocks, downed timber, stumps and other obstacles which can quickly bring an end to your riding season. Always think of what consequences are possible if you were to get caught and take a ride in an avalanche.

Until daily public forecasts begin, here are a few things to think about as the winter snowpack develops.

° Fall and a taste of winter have visited Colorado’s high country. Snow began to stick on the higher terrain by mid-September. Every season people have encounters with wintertime slab avalanches as early as August or September. Anyone traveling in the mountains, including hikers, hunters, sledders, skiers, riders and ice climbers, needs to be aware of the avalanche threat as soon as snow starts to accumulate on steep slopes.

° People are often misled when they see grass and brush sticking out of the snow surface. You should start thinking about avalanches any time you have snow resting on a steep slope. Remember, all you need is a slab resting on a weak layer of snow. The ground can easily act as a bed surface, even if it’s only a few inches below the snow surface.

° Old summer snow fields can act as the perfect bed surface too. Hard frozen old snow with new snow on top are common culprits in early season avalanche incidents.

° Early in the snow season there is not much snow on the ground. This means that rocks and stumps are near the snow surface. If you get caught in an avalanche you might get tumbled through rocks, stumps, and downed timber. These obstacles can do great bodily harm to backcountry users traveling through them at high speeds. Knee pads, helmets and full body armor may not be a solution to this problem. Even a very small slide can cause great harm if the terrain is unfriendly.Don't let an early-season injury ruin your winter!

° Wind drifts will create thicker slabs. Strong winds can take a three inch snowstorm and quickly build an 18” wind slab. Areas with shallow snow may be very close to deep drifted areas. It may be quite easy to move from a very safe area to a very dangerous area without traveling very far. Wind drifts will be denser than the new snow and thick hard snow on light fluffy snow is a great setup for avalanching.

° Once the sun returns after a storm cycle and warm temperatures cause the new snow to melt, look to see where the pockets of snow remain. The snow that lingers in sheltered areas and shady slopes could be the weak layer after the next snowfall. These areas could also become recurring problem areas throughout the winter depending on how the winter snowpack develops.

° Pockets of instability can develop quickly above early season ice climbs. Climbers should know the terrain above their route as rapid warming or heavy wind loading can quickly work to build slab or loose snow avalanches which can nudge a precariously perched climber into a bad fall.

° Hunters traveling across the high country need to exercise greater caution on steep terrain (steeper than 30 degrees with accumulated snow) when crossing ridges from one valley to another.