( trigger causes degrees snowpack avalanches slip off slab layer )
..........claim numerous lives every year when people get caught in a wall of
snow. There are three main.............. that produce avalanches. The first is the
................ On top of the snowpack is the icy layer followed by a third layer called
the ............ Having a weak layer of snow lying on top of the ice and bed layers
means that an avalanche is more likely to occur. A......... is needed for the
slab layer of snow to.................. . Most avalanches occur on slopes that have
angles of 25 to 60 ......................