The Importance of Tracking Early Season Weak Layers in the Snowpack… How Long do They Persist?

This video and text was originally published on the Utah Avalanche Center website

This is a presentation from Utah Avalanche Center director Mark Staples on tracking early season snow and how it may form persistent weak layers as well as how those layers heal.

It’s October and it’s snowing in the mountains. Early season snow is exciting, but it can also be deadly. In the last 10 years over 60% of avalanche fatalities in Utah have involved avalanches breaking on early season snow. Avalanches that happen on old, early season snow, are often extremely large, wide, and deadly.

In Utah, we often get snow in October and early November followed by a dry spell. In many places this snow melts, but in other places where it sticks around the snow begins to transform into weak, angular depth hoar. As our snowpack begins to stack up on top of this weak snow, we have the perfect recipe for an avalanche, and depending on the conditions this problem can persist for months. As we enter into the mountains we need to know what’s under our feet and where these early season weak layers exist.

1. Identify the pattern. Use satellite images, photos, and the avalanche forecast to identify the pattern of where this snow existed and where it didn’t.
2. Know your aspect. once you identify the general pattern of where early season snow exists use a compass and or map to know the aspects of different slopes.
3. Dig to verify. After identifying the pattern and knowing the aspects, hunt for these layers by digging to the ground.