Snow falling at the rate of an inch or more per hour increases avalanche danger. Snow crystals in the shape of needles and pellets result in more unstable snow conditions than the typical star-shaped snowflakes. Snow saturated with water can avalanche, especially on south facing slopes and beneath exposed rock. Rapid changes in wind, temperature and snowfall cause changes in the snowpack and may affect stability. If the snow cracks and the crack runs as you step, the danger of slab avalanche, the most serious type of winter hazard, is high.
Gullies are many times more hazardous than open slopes because they act as natural avalanche chutes.
It is a lowering of the inner body core temperature beyond where you can not produce enough heat to stay alive. Dress with adequate clothing when going skiing that will insulate you from the cold. Use materials that will keep you warm even if you get wet. It occurs when your extremities lose heat faster than it can be replaced by circulating blood. It may occur from direct exposure to cold or high wind.