Avalanche Advisory Archive Pre-2016

Date Issued:2011-03-30
Danger:4
Trend:3
Probability:4
Size:2
Problem:0
Discussion:

TODAY, RAIN SHOWERS. HIGHS AROUND 46.SOUTHEAST WIND 10/20MPH.

TONIGHT,RAIN SHOWERS.LOWS AROUND 36. SOUTHEAST WIND 10/15MPH.

THURSDAY, RAIN SHOWERS. HIGHS AROUND 44. SOUTHEAST WIND 10/15 MPH.

THURSDAY NIGHT...RAIN SHOWERS. LOWS AROUND 35. SOUTHEAST WIND
10 MPH.

We received the first freezing temperatures in 5 days last night at tram summit elevations and higher.

We have seen a great deal of above freezing temperatures down low. Much of the lower elevation snowpack is quite moisture saturated at this time and deteriorating rapidly.

At upper elevations we received a little new snow last night. This new snow will not bond well and tend to sluff off of trees, rocks, and steep open faces. Be aware these sluffs quite easily become point release avalanches and can entrain quite a bit of mass in longer pitches.

Recognizing the lower snowpack has seen a lot of above freezing temperature and is becoming quite rotten, expect to see any point release avalanches coming through these lower elevations cleanout the rotten snow.

Although danger is high meaning natural avalanches are likely, larger slides are not predicted. Yet with constant precipitation for the next few days, the ability to trigger deeper weak layers exists.

Expect to see activity peak during the warmest part of the day as diurnal fluctuation remains strong with 8-10 degree daily temperature swings.

Tip:

Wet Snow Avalanche:

Most avalanche professionals make a hard distinction between dry snow and wet snow avalanches because they are such different beasts. They are caused by different processes, they fail and fracture differently, they are triggered differently and they move differently down the slope. Really, there is a continuum between wet and dry avalanches and professional workers use the words: dry, damp, moist, wet and saturated to describe the continuum. Wet avalanches cause relatively few avalanche fatalities, consequently, they are studied less and are not as well understood.

Dry Avalanches:

What causes them?

Caused by putting too much additional stress on the snowpack.

How do they involve people?

Triggered by the victims or someone in the victim?s party in 90 percent of cases.

What are the contributing weather factors?

Usually loading of wind drifted snow or loading of new snow.

How do they flow?

Fast (80 mph or so) usually with a dust cloud.

WET SNOW AVALANCHES:

What causes them?

Caused by decreasing the strength of the snowpack.

How do they involve people?

Difficult for people to trigger. Most accidents are from natural avalanches.

What are the contributing weather factors?

Usually by rain, prolonged melting by sun or very warm temperatures.

How do they flow?

Slower (10-40 mph) like concrete and usually without a dust cloud.