Archived

Avalanche Forecast

Dec 31st, 2014–Jan 1st, 2015

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

4: High

The avalanche danger rating below treeline will be high

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

Regions: Northwest Coastal.

A number of weak layers will be tested by this storm, choose terrain defensively for the next few days. Ratings are based on significant snow accumulations on Thursday, if the storm is delayed until Thurs. night, ratings may be a touch over done.

Confidence

Poor - Timing of incoming weather systems is uncertain on Thursday

Weather Forecast

Synopsis: Warm air riding up and over the arctic air has created an above freezing layer at upper elevations that should stick around through Thursday morning. Looks like we swing back into the storm track Thursday night. Back to back storms through Tuesday should add some much needed volume to our snowpack. Thursday: Freezing Level: 800m, Precipitation: 4 to 10mm | 4 to 15cm; Wind: Treeline: Moderate W/SW | Ridgetop: Extreme, SW.Thursday Night: Precipitation: 5 to 15mm | 5 to 20cm.Friday: Freezing Level: 800m; Precipitation: 2 to 10mm | 2 to 15cm; Wind: Treeline: Strong, W | Ridgetop: Extreme, WSaturday: Freezing Level: Valley Bottom; Precipitation: 1 to 4mm | 1 to 5cm; Wind: Treeline: Moderate, NW | Ridgetop: Strong, NW.

Avalanche Summary

No new avalanche activity to report from Tuesday. On Monday wind and storm slabs to size 2.5 ran on NW, SW and SE facing aspects between 1500 and 2000m.

Snowpack Summary

Strong outflow winds on Dec. 28 left a variety of wind affected conditions in their wake in wind exposed terrain at all elevations. You will likely find wind pressed snow on north aspects, thicker wind slabs on south facing features and some degree of crossloading on everything else.At and below treeline widespread surface hoar has been reported which will likely be a player with the incoming storm system.The mid December crust can be found down around 30 to 80 cm and is sandwiched with facets and surface hoar.The mid November crust down 70 to 175 is gaining strength but is still reactive in test profiles. It is likely trending towards dormancy.

Avalanche Problems

Storm Slabs

New snow will begin to hide a variety of wind slabs at upper elevations and surface hoar at and below treeline. This combination will likely result in touchy storm slabs as the snow totals begin to stack up.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>Watch for areas of hard wind slab in steep alpine features.>Avoid open slopes and convex rolls at and below treeline where the new storm snow may be falling on surface hoar.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 4

Persistent Slabs

A series of crusts in the upper and middle snowpack may be reactivated by the storm. Surface avalanches in motion have the potential to step down creating large destructive avalanches.

Caution around convexities, ridge crests, rock outcroppings and anywhere else with a thin or variable snowpack.>Be aware of the potential for full depth avalanches due to deeply buried weak layers.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Unlikely - Possible

Expected Size: 1 - 6