• Backcountry Avalanche Forecast
  • Forecast Discussion
  • Observations & Weather Data

Tue, Dec 10, 2019 at 7:20 AM
Issued by: Jason Konigsberg

Today

 

Tomorrow

Considerable (3) Dangerous avalanche conditions. Cautious route-finding and conservative decision-making essential.   Moderate (2) Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully.
Considerable (3) Dangerous avalanche conditions. Cautious route-finding and conservative decision-making essential.   Moderate (2) Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully.
Moderate (2) Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully.   Moderate (2) Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully.
  Danger Scale

  • No Rating
  • 1
    Low
  • 2
    Moderate
  • 3
    Considerable
  • 4
    High
  • 5
    Extreme

Summary

Avoid steep slopes that face a northerly or east direction where there is wind-deposited snow. Any avalanche that you trigger in drifted snow can eventually break at the ground resulting in a large and dangerous avalanche. You can identify where slabs of wind-drifted snow exist by looking for a smooth and pillowy appearance to the snow surface. Slopes that sits near ridgetop, with a cornice above, are likely to have these denser and thicker slabs. Other signs of unstable snow include shooting cracks and sounds of the snowpack collapsing underneath of you.

Although the largest and most dangerous avalanche conditions are on north, northeast and east-facing slopes, don't let your guard down on southerly slopes and also below treeline. Recent winds drifted snow into slabs over crusts on southerly slopes. These avalanche may not break at the ground but they can take you for a rough ride. Also pay attention to open areas below treeline. These places may have thicker slabs that can collapse weaker snow layers near the ground.

 

 

Avalanche Problem

 
problem icon
N
S
E
W
NW
NE
SE
SW
Above Treeline
Near Treeline
Below Treeline
Certain
Very Likely
Likely
Possible
Unlikely
Historic
Very Large
Large
Small
Avalanche Character Aspect/Elevation Likelihood Size

What You Need to Know About These Avalanches


Persistent Slab avalanches can be triggered days to weeks after the last storm. They often propagate across and beyond terrain features that would otherwise confine Wind and Storm Slab avalanches. In some cases they can be triggered remotely, from low-angle terrain or adjacent slopes. Give yourself a wide safety buffer to address the uncertainty.

Avalanche Problem

 
problem icon
N
S
E
W
NW
NE
SE
SW
Above Treeline
Near Treeline
Below Treeline
Certain
Very Likely
Likely
Possible
Unlikely
Historic
Very Large
Large
Small
Avalanche Character Aspect/Elevation Likelihood Size

What You Need to Know About These Avalanches


Wind Slab avalanches release naturally during wind events and can be triggered for up to a week after a wind event. They form in lee and cross-loaded terrain features. Avoid them by sticking to wind sheltered or wind scoured areas.

Avalanche Problem

 
problem icon
N
S
E
W
NW
NE
SE
SW
Above Treeline
Near Treeline
Below Treeline
Certain
Very Likely
Likely
Possible
Unlikely
Historic
Very Large
Large
Small
Avalanche Character Aspect/Elevation Likelihood Size

What You Need to Know About These Avalanches


Loose Wet avalanches occur when water is running through the snowpack, and release at or below the trigger point. Avoid very steep slopes and terrain traps such as cliffs, gullies, or tree wells. Exit avalanche terrain when you see pinwheels, roller balls, a slushy surface, or during rain-on-snow events.

Weather Forecast for 11,000ft Issued Tue, Dec 10, 2019 at 12:45 PM by Jason Konigsberg Statewide Weather Forecast
  Tuesday Night Wednesday Wednesday Night
Temperature (ºF) 7 to 12 26 to 31 5 to 10
Wind Speed (mph) 10 to 20 10 to 20 5 to 15
Wind Direction W W W
Sky Cover Partly Cloudy Increasing Overcast
Snow (in) 0 0 0 to 1

Archived Forecasts

  • Select Forecast: Valid

Tue, Dec 10, 2019 at 8:13 AM
Issued by: Jason Konigsberg Statewide Weather Forecast  

The last storm left the Northern Mountains with anywhere from 6 to 12 inches of snow. Parts of the Steamboat zone, from Rabbit Ears to Buffalo Pass picked up anywhere from 14 to 24 inches. Along with all of this new snow came strong west to northwest winds. The combination of snow and wind is surely testing weak layers buried in our snowpack.

And a variety of weak layers we have. Old October snow turned into depth hoar and sits at the base of our snowpack. This is generally on shady slopes and east-facing slopes. Also we have several weak layers buried in the middle and upper portions of the pack. These layers are near-surface facets and even layers of surface hoar. These mid to upper pack layers spread around the compass to southerly slopes as well. On southerly slopes, particularly southeast, facets sits on melt-freeze crusts, providing a potential failure layer for newly wind-drifted snow. We haven't seen much avalanche activity on these sunny slopes yet, but caution is advised with the addition of wind-drifted slabs on Monday and continuing through today.

Although we haven't seen avalanches on sunny slopes, we have seen numerous avalanches on our shady and east-facing slopes. Sadly, one such avalanche resulted in the death of a skier near Cameron Pass. Conditions around Cameron Pass are not much different than other parts of the Northern Mountains region. Thick slabs of wind-drifted snow sit on numerous faceted layers and then large depth hoar at the ground.

On Monday a skier was nearly caught in an avalanche near Berthoud Pass. There have also been reports of remotely triggered avalanches from Vail Pass to Rabbit Ears Pass. All of this activity on its own should give us pause. The snowpack is reactive, avalanches are happening, and the loading from wind continues. Stick to conservative terrain choices for time being and make sure to heed obvious signs of unstable snow such as recent avalanches, shooting cracks in the snow and sounds of the snowpack collapsing.

 


  • Natural avalanche in Dave's Wave near Loveland Pass, 07 Dec 2019. (full)
  • A backcountry tourer triggered this avalanche around a windloaded terrain feature. Vail & Summit County Zone, 12/06/2019 (full)

See more photos & videos

Five Day Trend

Saturday

Sunday

Monday

Today

Tomorrow

danger icon danger icon danger icon danger icon danger icon
danger icon danger icon danger icon danger icon danger icon
danger icon danger icon danger icon danger icon danger icon

  • No Rating
  • 1
    Low
  • 2
    Moderate
  • 3
    Considerable
  • 4
    High
  • 5
    Extreme
Avalanche Observations
Report Date # Elevation Aspect Type Trigger SizeR SizeD
View Tue Dec 10 - >TL NE SS N R2 D2
View Tue Dec 10 - >TL SE SS N R3 D2
View Tue Dec 10 - >TL SE SS N R3 D2
View Sun Dec 8 - TL E SS AS / r R1 D1

See All Avalanche Observations

Field Reports
Report Date Observer Snowpack Obs Avalanches Media
View Tue Dec 10 Jason Konigsberg No Yes (1) No
View Tue Dec 10 Nikolaj Roell No Yes (1) Yes (2)
View Tue Dec 10 Bruce Hodgkins No No Yes (3)
View Tue Dec 10 - No Yes (1) Yes (2)
View Tue Dec 10 Ben D No No Yes (1)

See All Field Reports

Weather Observations
Station Date Time Temperature Relative Humidity Wind Speed Wind Direction Max Gust 24 Hr Snow
A-basin Sa-summit Wed Dec 11 2:00 AM 10 71 8 283 13 -
Vail Pass - Cdot Yard Wed Dec 11 2:00 AM 8 93 1 105 2 -
Copper Mountain Wed Dec 11 1:00 AM 9 - - - - 2.0
Fremont Pass Wed Dec 11 1:00 AM 11 - - - - -
Grizzly Peak Wed Dec 11 1:00 AM 14 - - - - -
Hoosier Pass Wed Dec 11 1:00 AM 18 - 1 29 - -
Vail Mountain Wed Dec 11 1:00 AM 21 - - - - -

See All Weather Observations