• An avalanche on a mountainAvalanche dans le Paine Grande image by Fr??d??ric LEVIEZ from Fotolia.com
  
  An avalanche is a fast flowing of snow that goes down the slope of a mountain triggered by nature or human activity. Avalanches move so quickly and with such momentum that they can move rocks and ice, destroy property and trap animals and humans according to the Regional Emergency Medical Services Authority (REMSA). There are certain weather conditions that can lead to an avalanche that you should look out for when traveling on a snow-covered mountain.
  
  

Snowstorm

• Most avalanches occur during or after a heavy snowstorm. According to the National Snow and Ice Data Center (NSIDC), the most avalanche danger occurs within 24 hours of the snowstorm. Consider postponing a hiking or skiing trip if there is a heavy snowstorm predicted for the day or night before a trip to reduce the chances of being caught in an avalanche. When snow accumulates over the course of days and weeks, it forms a packed layer referred to as a snowpack. According to REMSA, the stability of a snowpack is one of the best ways to predict an upcoming avalanche. When a local weather service posts a heightened avalanche warning, it is often because of snowpit and shear tests on the snowpack. Unless you are well-versed in snowpack testing, consult a local expert before assuming mountain safety.
  
  

Amount of New Snow

• New snow on top of an existing snowpack can lead to a slab of snow breaking off and falling down the slope. Snowfall of more than 1 foot in a mountainous area can make the most dangerous situation. Six to 12 inches of snow can potentially be a threat to recreationists and skiers, according to the NSIDC. Less than 6 inches of snowfall is a much safer amount, because there is little chance of an avalanche.
  
  

Temperature

• There are several temperature factors to watch out for in a potential avalanche situation. When a warm front moves through a snow-covered area, the temperature increases gradually and melting can begin within a snowpack. This will weaken the structure and lead to an increased chance of avalanche. A snowpack tends to stabilize again when it melts a little during the day and refreezes at night. If the temperature remains below freezing during the day, a snowpack may be less stable and more prone to avalanche, according to the NSIDC.
  
  

Wind

• On a mountain, wind typically blows from one side of the slope and down the other. The side with the wind is called the windward side, and the side the wind goes down is called the leeward side. When the wind blows, it packs snow unevenly on the leeward side, which increases the chances of an avalanche, according to the NSIDC. There is much less uneven snow on the windward side, so it is best to travel on that side to avoid an avalanche. In the Northern Hemisphere, the leeward side is typically the northeast, east or southeast slope.