Archived Forecast - Archived in relation to a fatal incident on this day

Backcountry Avalanche Forecast
Central Cascades

Issued: Sunday, February 16, 2025 - 8:14PM
Expires: Monday, February 17, 2025 - 8:14PM
Author: Gabriel Coler

THE BOTTOM LINE

Avalanche danger will continue to rise overnight and on Monday as new snow piles up.  Avalanches large enough to bury or injure a rider are possible throughout all elevations, and likely wherever the wind has blown in deeper deposits of snow.  Monday will be a good day to start with conservative terrain choices, and only move to bigger or steeper slopes when/if you feel confident that it is safe to do so.

Avalanche Forecast

Avalanche Danger - Monday, February 17, 2025
Above Treeline3 - Considerable
Near Treeline3 - Considerable
Below Treeline3 - Considerable

Avalanche Problems (2)

Problem #1: Wind Slab
Aspect/Elevation: Near and Above Treeline, all aspects except West
Likelihood: Likely
Size: Small (D1) to Large (D2)

Even Light winds can move snow onto leeward slopes.  Older Wind Slabs may remain reactive due to the weak nature of last week's surface snow.  On Monday Wind Slabs will grow with the heavy snowfall and Light winds from the West.  While most of us have no desire to ride up high where the visibility is poor, Wind Slabs can occur near treeline and even below treeline where the wind has open space to blow (passes, burns, and wrapping around our cones and buttes).

Watch for variable deposition of the new storm snow, as well as stiffer snow or cracking that can indicate wind deposited and packed snow.

Problem #2: Storm Slab
Problem Type
Storm Slab
Aspect/Elevation: Near and Below Treeline, all aspects
Likelihood: Likely
Size: Small (D1) to Large (D2)

Forecasts are calling for over a foot of new snow in the next 24 hours.  Often when is snows at heavy rates, the landscape and older snowpack need time to "come to terms" with this added load.  On Monday, I'll be looking primarily for cohesion in the new snow (can it form a slab).  If it seems cohesive, I'll be avoiding the steepest and most convex slopes.  Hand shears, and shovel tilt tests are great ways to look further into the problem and see if there is a weak layer.

On Sunday I didn't observe any collapses, cracking, or avalanches, but there was obvious hard over weak layering even in the older snow that was on the ground.  New snow will continue to increase the load over the cold, weak snow from last week (down just under a foot on Sunday).

Lastly, remember that even relatively small Storm Slab avalanches can have worse consequences when terrain traps like trees, cliffs, and gullies are present; as they often are below treeline.

Weather Forecast

We can expect heavy snowfall overnight and during the day Monday.  I think the point forecasts are a bit overblown, but even the lower forecast values will total over a foot in the next 24 hours.  The winds near treeline are forecast to be Light from the West, but we'll likely see gusts that are Moderate, as well as Moderate winds at alpine elevations. Snow levels will hover around 4000 ft. on Monday.