Colorado Front Range Avalanche Bulletin - Archived, Expired

Backcountry Avalanche Forecast
Tue, Feb 16, 2021 at 6:54 AM
Issued by: Ben Pritchett

Danger Rating
Tuesday, Wednesday
All elevations
Considerable (3) - Dangerous avalanche conditions. Cautious route-finding and conservative decision-making essential.

Summary

Light snowfall on a snowpack near its tipping point means that avalanche conditions are dangerous. Very large avalanches could run naturally. If you travel in avalanche terrain, you can easily trigger deep avalanches that break near the ground and run far. You can even trigger them from the lower-angled slopes below, so pay close attention to any exposure to big terrain overhead. Steep wind-loaded slopes can produce the largest avalanches, but even in wind-sheltered terrain you can easily trigger an avalanche big enough to bury you. Avoid travel on or below slopes steeper than about 30 degrees.

Sadly there were two avalanche fatalities this weekend, in two avalanche accidents. Both accidents shared common characteristics. A large and deep avalanche broke near the ground, entraining the entire season's snowpack. Our deepest condolences go out to the friends and families of both victims.

Avalanche Problem
Persistent Slab
N -> SE, All elevations
Likely
Large - Very Large

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.

Forecast Discussion
Tue, Feb 16, 2021 at 8:03 AM
Issued by: Ben Pritchett Statewide Weather Forecast  

Light loading on a snowpack that is near its tipping point presents a challenge. It will be difficult to nail down when or if the house of cards will fall on its own. Will we see natural avalanches today?

There is no doubt the snowpack rests atop a weak base. Widespread slab development is well documented. We have resounding evidence that you can easily trigger large to very large avalanches. The accidents this weekend make it impossible to shy away from the consequence.

There is uncertainty about whether the light snowfall and modest winds will tip the balance for natural avalanches. Our team thinks there's a chance for a few to fall down the mountainsides today, but generally not enough new loading to initiate a widespread natural avalanche cycle.

The danger hovers precariously near the high end of Considerable, or level 3 of 5. If you wind up in an area with locally heavier snowfall (like in the Park Range or Flat Tops), or if the west to northwest winds appear to efficiently drift snow beneath ridges nearby, consider the balance may tip. Stay wary to the threat of natural avalanches and the weather factors that could set them off.