Avalanche Forecast

Issued: Nov 25th, 2014 8:58AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs and Loose Dry.

rbuhler, Avalanche Canada

Cariboos.

Stormy weather will drive avalanche danger up this week. It's a good time for riding low angle slopes and avoiding overhead exposure.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

A warm front will move over the southern part of the province midday Wednesday. The Cariboo region is not expected to see the warm temperatures but will get the heavy precipitation as the moist air mixes with the colder Arctic air. This will persist through Thursday before the Arctic front pushes down from the north on Friday. Wednesday: Precipitation 3-6mm, freezing levels valley bottom, ridgetop wind light SW-WWeds. Night: Precipitation 10-15mm, ridgetop wind moderate SWThursday: Precipitation 15-25mm, freezing levels valley bottom, ridgetop wind strong SWFriday: A mix of sun and cloud, snow flurries possible, freezing level valley bottom, ridgetop wind light variable

Avalanche Summary

One observer in the Raft Mountain area observed several small natural avalanches and easily triggered a few more on steep road banks on Saturday. There are no new observations from higher terrain but given the amount of new snow in the past few days it's likely that there was some sort of natural avalanche cycle. Natural avalanche activity is expected to increase as the storm snow continues to accumulate.

Snowpack Summary

This is an estimate of what the snowpack may look like based of a few observations and previous weather. If you plan on riding in avalanche terrain be sure to supplement this with your own observations and please pass along any data you collect (forecaster@avalanche.ca). Around 50-80cm of recent storm snow sits on the mid-November drought layer (facets, surface hoar, and/or a sun crust on steep southerly slopes). Below this is 20-30 cm of old snow, which is probably quite weak and facetted (sugary). A thick rain crust which formed a few weeks ago is now down 70cm or more. The average snowpack depth at treeline is now around 90-120cm. Recent strong and variable winds have probably created dense wind slabs in exposed terrain and resulted in variable snow distribution. At lower elevations expect travel to be difficult and potentially hazardous as many early season hazards are exposed or lightly buried (stumps, logs, rocks, open creeks, etc).

Problems

Storm Slabs

The developing storm slab sits on a touchy weak layer and is expected to become very reactive with additional storm loading. Recent wind loading has created wind slabs in leeward features which are expected to be very touchy.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>Be alert to conditions that change with elevation.>Choose conservative lines and watch for clues of instability.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

3 - 6

Loose Dry

Be cautious of loose sluffing from steep terrain as new snowfall continues.

Be cautious of sluffing in steep terrain.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 4

Valid until: Nov 26th, 2014 2:00PM