GCSE Geography

  1. what are avalanches
    masses of snow , ice and rocks that move downhill at speeds pof up to 300kmph
  2. loose snow avalanche
    a powdery avalanche operating from a single point
  3. slab avalanche
    a large scale avalanche formed when a slab of ice and snow breaks away from the main ice pack
  4. causes of avalanche
    • heavy snowfall
    • steep slopes
    • tree removal
    • temperature rise
    • heavy rainfall
    • human factors
  5. if there is heavy snowfall this can cause an avalanche because
    • this adds to weight of earlier snowfalls
    • uneven rates of freezing , together with occasional melting can create distinct layers within the snow and ice making slab avalanches more likely to happen as one layer can slip other the other
  6. avalanches are more likely to occur on steep slopes in acess of
    30 degrees
  7. the removal of trees for ski developments enables
    avalanches to move downhill unimpeded . When present on a hillside , trees can break up an avalanche and prevent it from becoming large
  8. sudden rises in temperature and associated to
    melting lead to avalanches in the spring
  9. heavy rainfall can
    lubricate a slope and trigger an avalanche
  10. almost all deaths from avalanches kill the people who actually triggered them . Off piste skiing is a major cause of avalanches because it often involves skiing in
    areas of fresh snow that have not been assesed for the avalanche
  11. to reduce the avalanche hazard we use
    • avalanche gully
    • fences
    • walls
    • breaking or retardent mounds
    • afforestation
    • wedge
    • direct protection
    • avalanche shed
  12. fences and walls
    break up the snow
  13. avalanche gully allows
    snow to build in the trench before affecting the land
  14. afforestation
    roots stop the ice sliding
  15. avalanche shed
    acts as a bridge or shelter so that everything underneath it will be protected
  16. breaking or retardant moulds and direct protection
    slow down the avalanche and break it up into smaller pieces
Card Set
GCSE Geography