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

Fri, Apr 30, 2021 at 6:48 AM
Issued by: Kreston Rohrig

Friday

 

Saturday

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.   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.
  Danger Scale

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

Summary

Temperatures climbing into the 50s above 11,000ft and a weak to no freeze overnight will increase your chances of triggering a wet avalanche today. Higher elevation slopes with more loose snow at the surface will see the most wet avalanche action as slopes become damp and unstable. This problem will grow in size as wet snow or water penetrates further in the snowpack.  Expect avalanches to gouge deeper, creating more massive slides later today through tomorrow.

If you see rollerballs tumbling out of steep, rocky terrain or find yourself sinking into unsupportive, slushy snow, it's best to steer clear of steeper terrain. Even small avalanches can be dangerous if they hit you from above or take you for a ride through rocks or trees.

----------------

The CAIC will transition to regional products this afternoon (April 30). Regional backcountry forecasts are issued by 4:30 PM with avalanche danger ratings for the following day.

 

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.

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


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.

Weather Forecast for 11,000ft Issued Sat, May 1, 2021 at 2:33 PM by Mike Cooperstein Statewide Weather Forecast
  Friday Night Saturday Saturday Night
Temperature (ºF) -- -- --
Wind Speed (mph) -- -- --
Wind Direction -- -- --
Sky Cover Overcast Overcast Overcast
Snow (in) -- -- --

Archived Forecasts

  • Select Forecast: Valid

Fri, Apr 30, 2021 at 7:30 AM
Issued by: Kreston Rohrig Statewide Weather Forecast  

Today is the last day of zone forecasting for the season, and what a wild ride it's been. We will continue to put out a regional forecast for the Northern, Central, and Southern Mountains each day by 4:30 PM for the following day. Be sure to stay tuned and check the forecast before you head out. There are still plenty of hazards you need to manage in the mountains right now, and solid spring stability is still a ways out.

The pinnacle of this warmup is ramping up today through tomorrow. With temps punching up into the 50s and possibly 60s above 11,000ft, wet avalanches should be at the forefront of your mind. Any lingering loose, soft snow at the surface at higher elevations that haven't baked out already will be the first to shed. Keep an eye on steep rocky faces for rollerballs or minor point releases as indications of decreasing stability. As the warming penetrates further into the snowpack, these small loose wet avalanches could turn into much bigger monsters if they gouge deeper into wet, cohesionless snow.

The other thing to keep in mind is the suspect Persistent Slab structure lingering on high elevation northerly slopes. We continue to find layers of facets sandwiched between crusts or hard slabs around 1 to 2 feet deep. There hasn't been a reported avalanche for over a week on these layers, but things could change during this warmup. Cold, dry snow on these aspects could produce larger wet slabs if water makes its way down to these layers today or tomorrow. Again, something to think about if you're planning on a mission to steeper terrain on this part of the mountain. Finding this layer isn't hard as you only need to dig down a foot or two.

Timing is critical right now. Be sure to get out early, and be prepared to bail off of steeper terrain if you see any indications of wet, unstable snow.


  • Slide track. (full)
  • Image of the snowpack next to the small avalanche. The top 11 cm of new snow was turning wet. The avalanche‚Äôs bed surface was ~25 cm below the new snow was K hard MFcr, with ~25 cm of 1F hard WG and 4F-1 hard WG to the bottom of the pack. (full)
  • Skier triggered WL avalanche. The location of where the avalanche started is visible in this picture. (full)

See more photos & videos

Five Day Trend

Tuesday

Wednesday

Thursday

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
No relevant backcountry observations found for this forecast

See All Avalanche Observations

Field Reports
Report Date Observer Snowpack Obs Avalanches Media

See All Field Reports

Weather Observations
Station Date Time Temperature Relative Humidity Wind Speed Wind Direction Max Gust 24 Hr Snow
Storm Peak Observatory Fri May 14 6:05 AM 40 - 12 225 15 -

See All Weather Observations