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

Fri, Apr 30, 2021 at 6:59 AM
Issued by: Bo Torrey

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

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Summary

Expect wet avalanche conditions as daytime temperatures reach into the mid-50’s at 11,000 feet. As the snow warms avalanches can break more than a foot deep on previously drifted slopes, or produce deep-gouging avalanches where you find a loose and unsupportive snowpack, especially around steep rock features.  An early start and exit will help you to avoid most of the avalanche danger. 

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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


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


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 7:53 AM
Issued by: Bo Torrey Statewide Weather Forecast  

Above-average temperatures today and tomorrow will create wet avalanche conditions. The main concern will be Loose Wet avalanches that occur as the snowpack heats up and becomes wet and unsupportive on steep slopes. Although the avalanches may be relatively small they can still pack a punch with the dense, heavy snow as they build up speed. Even a small avalanche can be dangerous if it catches you in consequential terrain and pushes you into trees or rocks.

The warm temperatures will also allow meltwater to percolate down into deeper layers of the snowpack. Upper-elevation northerly-facing aspects still hold a relatively dry snowpack below the top 12 inches or so, and as meltwater works its way down through the dry snow and saturates layers it creates the potential for large Wet Slabs avalanches on steep slopes. It’s difficult to predict the exact timing of when Wet Slabs will occur but warm daytime temperatures and consecutive nights of above-freezing temperatures are the kinds of conditions we look for to forecast them. If you notice upper elevation northerly-facing slopes becomes wet and saturated steer clear of consequential slopes until temperatures freeze and the snowpack solidifies again.

Since mid-April, we have documented a couple of layers of buried facets in the upper part of the snowpack on north-facing slopes. Avalanche activity on these layers has slowed since last week and the warming temperatures should help to put them to rest but that doesn’t mean they’re completely gone just yet. If you’re traveling to high elevation north-facing slopes and find 8 inches or more of recently drifted snow it’s a good idea to get your shovel out and dig down to inspect the snowpack for these layers of facets and avoid steep slopes if you find them. 

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.

 


  • Natural wind slab avalanche that likely ran on April 23 or 24. (full)
  • Loose wet avalanche on northeast facing slopes above treeline. Likely ran early on April 25, 2021 (full)
  • SS-N-R1-D1 SE ATL Prospector Mountain (full)
  • A couple small wet loose avalanches in the Sawatch Range on April 24, 2021 (full)
  • Series of small storms over last 10 days have added up to 8-10 inches of recent snow above a crust. The layer where the saw is input is a thin layer of facets. The facets were unreactive in stability tests throughout my travels. April 23, 2021 (full)

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Five Day Trend

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    Moderate
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    Extreme
Avalanche Observations
Report Date # Elevation Aspect Type Trigger SizeR SizeD
View Wed May 5 - >TL N SS N R1 D1.5

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Field Reports
Report Date Observer Snowpack Obs Avalanches Media
View Thu May 6 Jason Konigsberg No Yes (1) Yes (1)
View Wed May 5 Jason Konigsberg No Yes (1) No

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Weather Observations
Station Date Time Temperature Relative Humidity Wind Speed Wind Direction Max Gust 24 Hr Snow
Leadville Fri May 7 3:00 AM 30 48 5 60 - -

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