It might take several weeks before another heavy snowfall. The danger
comes when the third layer of snow falls. If it is made of light, loose or fluffy
snow (not heavy wet snow), the danger starts. This third layer is called the “weak
or slab layer.” A weak layer of snow lying on top of ice and bed layers means that
an avalanche is more likely to occur.
The Trigger and Angle
A trigger is needed for the slab layer of snow to slip off. This means something
causes the slab to slide off the second thin layer of ice. This is the second cause of
an avalanche. The pressure from the weight of a skier can easily cause the top slab