Avalanche Advisory Archive Pre-2016

Date Issued:2013-02-25
Danger:2
Trend:4
Probability:1
Size:2
Problem:0
Discussion:

TODAY...MOSTLY CLOUDY. SCATTERED SNOW SHOWERS IN THE MORNING.
SCATTERED RAIN AND SNOW SHOWERS IN THE AFTERNOON. HIGHS AROUND 37. SOUTHEAST WIND 10 MPH.

TONIGHT...CLOUDY. CHANCE OF SNOW AND RAIN LATE. LOWS AROUND 30.
SOUTHEAST WIND 10 TO 20 MPH.

TUESDAY...SNOW LIKELY IN THE MORNING. RAIN AND SNOW LIKELY IN THE AFTERNOON. SNOW ACCUMULATION TO 1 INCH. HIGHS AROUND 37. SOUTHEAST WIND 10 TO 20 MPH.

Temps at the Tram peaked just above freezing a little after noon yesterday, but have since dropped back off. Eaglecrest and Mt Juneau never made it above freezing.

We received minimal new snow from scattered showers in the start zones over the last 24hrs with only mild winds and overall the snowpack has had more time to settle and bond.

Looking forward; there is not a lot of precip forecast, but there is a good chance that we will get strong winds late tonight at ridgetop level creating the possibility of wind transport.

I am going to leave the Avalanche Danger at MODERATE today, but only because of tonights storm front: Natural avalanches unlikely, potentially destructive avalanches unlikely to come near or reach developed areas. In Urban Zones normal caution is advised.

Backcountry Travel is generally safe. Human triggered avalanches definitely still possible. Unstable slabs possible on wind loaded terrain. Normal caution is advised with particular attention to wind affected slopes, and ridgetops facing North.

Tip:

CORNICES
Cornice Fall Avalanches:

Cornices are the fatal attraction of the mountains, their beauty matched only by their danger. Cornices are elegant, cantilevered snow structures formed by wind drifting snow onto the downwind side of an obstacle such as a ridgeline.

Similar to icefall avalanches, the weight of a falling cornice often triggers an avalanche on the slope below, or the cornice breaks into hundreds of pieces and forms its own avalanche?or both. Be aware that cornice fragments often \"fan out\" as they travel downhill, traveling more than 30 degrees off of the fall line. Cornices tend to become unstable during storms, especially with wind, or during times of rapid warming or prolonged melting. Each time the wind blows, it extends the cornice outward, thus, the fresh, tender and easily-triggered part of the cornice usually rests precariously near the edge while the hard, more stable section usually forms the root.

Similar to icefall avalanches, cornice fall avalanches are infrequent and hard to predict. And similar to slab avalanches, the ones who get into trouble almost always trigger the avalanche themselves, in this case, by traveling too close to the edge of the cornice.

Cornices have a very nasty habit of breaking farther back than you expect. You need to treat them with an extra-large dose of respect. NEVER walk up to the edge of a drop off without first checking it out from a safe place. Many people get killed this way.

It's kind of like standing on the roof of a tall, rickety building and walking out to the edge for a better view. Sometimes the edge is made of concrete but sometimes the edge is made of plywood cantilevered out over nothing but air. It feels solid until, zoom, down you go. Check it out from a good vantage point first.

But cornices aren't all bad. You can use cornices to your advantage by intentionally triggering a cornice to test the stability of the slope below or to intentionally create an avalanche to provide an escape route off of a ridge.

Forecaster:Chris Eckel