Avalanche Advisory Archive Pre-2016

Date Issued:2013-02-12
Danger:1
Trend:3
Probability:2
Size:2
Problem:0
Discussion:

The National Weather Service Forecasts-

TODAY...DECREASING CLOUDS. AREAS OF FOG IN THE MORNING. HIGHS
AROUND 35. NORTHWEST WIND 10 MPH.

TONIGHT...MOSTLY CLOUDY. CHANCE OF SNOW AND RAIN. LOWS AROUND
28. SOUTHWEST WIND 5 MPH SHIFTING TO THE SOUTHEAST LATE.

WEDNESDAY...SNOW AND RAIN IN THE MORNING...THEN CHANCE OF RAIN IN THE AFTERNOON. SNOW ACCUMULATION TO 1 INCH. HIGHS AROUND 35. LIGHT WINDS BECOMING SOUTHEAST 5 MPH IN THE AFTERNOON.

Temperatures have fallen by 4c degrees over the last 3 days.

We received 90mm of precipitation in the last 4 days (nearly 4\") This left around 20cm of very dense snow at tram summit elevations and additional amounts at higher elevations but all quite dense and wind affected in places.

You can assume there are deep wind drifted pockets in places near summit and ridgeline. Some of which may still be sensative for human triggered avalanches in isolated places.

Todays forecast calls for temperatures to cool off over the next 24 hours and no significant precipitation... With only light winds avalanche danger is LOW at this time.

Natural avalanches are unlikely. Human triggered avalanches are also unlikely yet may be possible in very isolated places.

Tip:

Settlement and Sintering:

A newborn, snowflake that falls out of the sky doesn't stay that way for long. As soon as it lands on the snow surface it begins a rapid process of change. Just like people, as a snowflake ages, its beautiful, angular shape becomes progressively more rounded through time and it forms bonds with its neighbors. In people, it's called growing up; in the snowpack it's called \"sintering\"--forming bonds with neighboring crystals to create the fabric of the snowpack.

As sintering progresses, the snow becomes denser and stronger, which we call \"settlement.\" Sometimes you will hear people incorrectly use the term settlement to describe the catastrophic collapse of a snowpack that often makes a giant \"whoomph\" sound, as in, \"Hey, did you hear that settlement? Maybe we should get out of here.\" Instead, we call these collapses or \"whoomphing\", which, believe it or not, is actually the technical term for a collapsing snowpack. It sounds funny but it's a great description. Settlement is the SLOW deformation of the snow as it densifies and sags under the influence of gravity.

New, fluffy snow settles relatively quickly, within minutes to hours and it settles much more quickly at warm temperatures than in cold temperatures. We often think of settlement within the new snow as a sign of stability (at least within the new snow) because it means that the new snow is rapidly becoming stronger. When new snow settles, it forms \"settlement cones\" around trees and bushes where the snow bonds to the bush which props up the snow, like a circus tent.