How did the snowpack become so dangerous for avalanches near Tahoe?

A snow drought caused fragile crystal layers to form, and subsequent freezing rain added weight, creating a precarious structure susceptible to slides.

When did the conditions for the avalanche begin to develop?

The dangerous conditions began weeks before the avalanche, with a snow drought followed by freezing rain on February 10th.

What weather factors contributed to the avalanche risk?

Heavy snowfall rates, strong winds exceeding 100 miles per hour, and weak layers within the snowpack created a high avalanche danger.

Home / Environment / Tahoe Snowpack a Ticking Time Bomb

Tahoe Snowpack a Ticking Time Bomb

19 Feb

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Summary

A snow drought transformed fragile crystals into weak layers.
Freezing rain on February 10th added critical weight.
High winds and heavy snow created dangerous avalanche conditions.

The conditions leading to a recent avalanche were established weeks prior. A period of drought in California, influenced by the same weather pattern chilling the Eastern U.S., prevented significant snow accumulation after an initially snowy December and January. During this dry spell, fluctuating temperatures caused water vapor to form fragile 'facets' within the snowpack, resembling a precarious domino structure.

On February 10th, this fragile layer was compromised further when fresh snow arrived, followed by freezing rain in some areas. This ice added significant weight to the weak, buried crystals. Avalanche experts, surveying the area near the slide site, identified these dangerous layers and even triggered controlled avalanches to test the snowpack's stability.