I get pretty excited when temps start to drop, leaves start to fall and talk of snowflakes picks up. After all, this is one of the prettiest times of the year in the high country:
I used to spend hours watching satellite loops, anticipating when snow would start falling on my fave Mammoth Mountain. That attitude didn’t change when I moved here to Colorado, but should it?
Last season I took my AIARE Level I avalanche class and I have shifted my focus to the backcountry. In terms of avalanche safety and backcountry snowboarding, early season snow is typically a BAD thing… WHAT!!!! “How can that be?” you ask. Well, let’s talk snow science:
Snow is good, but snow doesn’t just fall from the sky lay on the ground and stay there. It is constantly changing (snow geeks call this metamorphism). Those little flakes that you see in a snowstorm are great, they typically bond well together and make for a pretty good snow layer, but what tends to happen early season is that they begin to “facet.” These facets do not bond well to each other or other layers and become little ball bearings for avalanches to slide on.
If you’ve been in the game long enough, you’ve heard the term facets before, but what causes them and why is it so bad with an early season snowpack?
1. Facets are caused by temperature differences between lower and upper layers of the snowpack (geek speak = temperature gradient). Check out this site for a cool video and a ton more info.
2. These gradients are especially bad with a thin snowpack (like early season).
3. Facets forming from this temperature gradient in the lower snowpack is called depth hoar. It sticks around and causes problems for a long time through the season (persistent) and is one of the major causes of injury/fatality causing avalanches
“Never trust a depth hoar snowpack, no matter how deep you bury her”
-Unknown Smart Dude
Overall, for resort riders, let it snow, let it snow, let it snow! For the backcountry types out there, let’s be a little more patient, if it’s going to snow, let it snow hard and keep snowing for months, otherwise lets hold off until it’s ready to dump.
So, in conclusion: Am I going to stop obsessing over early season snow? Probably not. Am I going to pay attention to what it does to the avalanche hazard in the backcountry… hell yes and so should you.