15 Apr 2012

The spring skiing has been very good, moving around to different elevations and aspects is key!!

As of 06:00 the temperature at 2280 meters was -6, winds were 10-15 KPH from the S.
At 1550 meters the temperature was -2.5, 77% relative humidity and the barometer is rising.
In the valley it is -1.

For the latest Avalanche Advisory click here: Avalanche Advisory

In the past 2 years in the States skiers are becoming the #1 statistic: US Avalanche Statistics

What does fresh tracks skiing cost: Interesting Comparison

Older footage but cool narration: In your backyard

Poor footage but an amazing slab release: Large Slab

From E Chapelle's work in 1960: Heat and vapour transfer in snow.

The flow of heat through snow is a complex process. Snow, particularly at low densities, is a good thermal insulator. Like other insulating materials, it transfers heat by a combination of molecular conduction through the solid framework, by conduction, diffusion and convection of the entrapped air, and by internal radiation exchange. Unlike other insulators, it also transfers heat by sublimation of the solids--in this case ice--and associated diffusion and convection of the vapor phase. The latent heat of sublimation of ice is high, 680 calories per gram at the freezing point; consequently water vapor can be an efficient means of heat transport within snow which introduces complicating factors in the bulk thermal conductivity. Owing to this contribution of water vapor to heat flow, the bulk, conductivity becomes dependent on absolute temperature as will be demonstrated below, Moreover, recrystallization of ice which has passed through the vapor stage rearranges the solid framework and effects a permanent time- dependent change of conductivity, In addition-to thermal effects, this latter change also profoundly alters the mechanical properties of snow: the stabilizing and strengthening effects of destructive crystal metamorphism are reversed and the snow becomes mechanically weaker.

Temperatures have kept the snow firm in the morning. When it does soften up and your timing is good the spring skiing is excellent. Good corn to be had in the back country as well.