We need to talk about the dangers of “little snow” – and this effects everyone regardless of season. It’s more dangerous in early winter, when it is coupled with extended periods of cold.
Even with not a lot of snow and pow, you can still bag awesome freeriding sessions (and it’s great for mixed climbing), as you can see in this freaky Frenchie clip:
(Note that they left their ice axes and crampons at home… their moms would be worried if they knew…)
Little Snow = Little Danger?
When there is little snow, you may think it’s safe because you associate avalanches with lots of snow. And you see rocks sticking out of the snow and will think to yourself “hey, those rocks will hold the slab in place.” Right? Bullshit. Here’s why a shallow snowpack can be dangerous especially if it’s cold out.
In a shallow snowpack, you have heat radiating from the ground, which can be around 0 or -1 degrees Celsius (or around 32 F). The air can be quite cold, let’s say -15 Celsius. Now, the 20-40 cm of snow between the ground and the air will “bridge” the temperature difference.
That means the bottom of the snowpack will be warm – close to 0 Celsius – and the top of the snowpack will be colder, pretty much the same as the air temperature. And the temperature of the snowpack in between will vary tremendously. And therein lies the problem.
Large Temp Variations in the Snow Are Bad
Huge temp variations in the snowpack will destabilize things. I won’t go into the science but let’s just say because it makes crystals funky and not bond well. In addition, you have rocks sticking out of the snow, which will collect heat from the sun and radiate that heat in the snowpack around them, messing up snowpack-temperatures even further.
OK, why is shallow snow dangerous when the snowpack is deep? The question sounds stupid, but here’s the thing: if you’re touring near ridges or windy places, the wind can blow almost all the snow from one place and deposit it somewhere else, leaving like 2 cm of snow in one section and a few steps later, 200 cm.
And here’s the thing: wherever you have a shallow snowpack “meeting” or forming right next to deep snowpack – or as we call it, transition areas, you’ll have different temperature snowlayers next to one another – and that again creates instability – the crystals next to one antoher will be differently shaped and will not bond well.
So in a nutshell: look out for areas with a thin snowpack (20-40 cm) when the air is cold (below -5 degrees Celsius) AND look out for transition areas where you have a shallow snowpack next to deep deposits of snow.
In our avalanche education system, we have danger patterns – these are weather scenarios/patterns that if you recognize, you’ll know where to look and will know where the danger spots are.
The 6th danger pattern is the shallow snowpack, especially when paired with cold air temperature. The sibling of this danger pattern is the transition between shallow and deep snowpack.
(Tis’ the only circumstance when little snow=no avy danger.)
We talk about these danger patterns and a lot more in our free online avalanche workshops, coming soon.
But till then you might wanna check out the 8 most typical mindtraps that get us into dangerous situations.
Did you know that most avalanche accidents could have been avoided? It is these mindtraps that you need to get conscious about to hack (a huge part of) the danger out there.
Click here to make one more step for your safety.