Recent temperatures in the Eastern Sierra have been swinging almost 40 degrees a day. Although spring skiing may seem casual, when the snow pack heats up this drastically, wet avalanches or wet slides can be a considerable danger in the backcountry.
Here’s a quote from the US Forest Service about wet avalanches:
“Wet avalanches usually occur when warm air temperatures, sun or rain cause water to percolate through the snowpack and decrease the strength of the snow, or in some cases, change the mechanical properties of the snow. Once initiated, wet snow tends to travel much more slowly than dry snow avalanches–like a thousand concrete trucks dumping their load at once instead of the hovercraft-like movement of a dry avalanche. A typical wet avalanche travels around 15 to 30 km/hr (10 or 20 mph) while a typical dry snow avalanche travels 100 to130 km/hr (60 or 80 mph)–big difference. Wet slides are also harder for a person to trigger than a dry slide. Because of these two facts, wet avalanches don’t account for nearly as many avalanche fatalities as dry snow avalanches. But they’re certainly not insignificant. They still account for a sizeable percentage of avalanche fatalities in maritime climates, especially to climbers. Wet slides can also do quite a bit of damage to property or to forests and often cause significant hazards on highways.” – http://www.fsavalanche.org/encyclopedia/avalanche.htm
This slide was triggered on the small, popular exit slopes below False White Mountain [Tioga Pass, CA]. Despite great corn at high elevations in the morning, the snow became drastically wetter and heavier the more we descended and the later it got. This was the final slope before a long a flat traverse back to the trail head – a good reminder to always stay alert.
6 thoughts on “Tioga Pass Wet Avalanche, April 27th, 2013 | Don’t Let Your Guard Down…”
Yep! The rotten snowpack is prevalent right now…had my experience on lap 3 on Sunday as the day became warmer…no slide just trenching to the dirt. Be careful out there…
Glad to read your message from 5/1…have you been back up to ski some more in or near Ellery Bowl or False White Mtn by chance?
Wet slides are nasty. Thanks forthe heads up.
Scary stuff. I had a wet slide pop out on me at Little Morrison by Mammoth one spring. Started small, ended up huge and trenching. Would have ground me to pieces. thanks for this report, Andrew.