Avalanches

1
Avalanches
2
What is an Avalanche?

• Large mass of rock debris or snow that moves
  rapidly down a mountain slope, sweeping and
  grinding everything in its path.

3
How Avlanches are Created

• An avalanche begins when a mass of material
  overcomes frictional resistance of the sloping
  surface, often after its foundation is loosened
  by spring rains or is rapidly melted by warm, dry
  wind. Vibrations caused by loud noises, such as
  artillery, thunder, or blasting can create an
  avalanche.
• Avalanches usually occur in February, March, and
  January. They can also occur in April when
  everything thaws.

4
Danger Level
5
Different Types of Avalanches
There are three different types of avalanches..

• A dry snow avalanche consists of powdery snow and
  air that can move faster than 100 MPH.

2. A wet snow avalanche is a mass of partially
melted snow that moves slower than a dry
snow avalanche.
3. A slab avalanche is when a portion of snow
breaks loose as a slab and splits into
pieces as it slides.
6
Three parts of an Avalanche
7
Areas in the world
Where Avalanches Occur

• Avalanches can occur anywhere in the world.
• They occur where ever there is a high snow
  covered mountain.
• Avalanches can also occur near plate boundaries.
  Usually at convergent plate boundaries.

8
Areas at High Risk
9
Damage Due to Avalanches
Avalanches dont do a lot of damage to cities or
towns because they are up in the high mountains
but anything up there better watch out.
Avalanches burry mountain side homes and destroy
forests. They also take down radio towers and
lodges that are in its path. Avalanches also take
away peoples lives, especially skiers who are
taking a trip down the mountain.
10
Three triggers for Avalanches

• These are three different ways that an avalanche
  can start.

11
Graph of Danger Zone
12
Deaths From Avalanches

• Avalanches cause a fair amount of deaths when
  they occur. They are so hard to predict and
  because of that people never know when they are
  going to happen. That is why it is best to never
  go onto a mountain alone.

13
Tips for Avalanche Survival

• If caught in an avalanche.
• Yell and let go of ski poles and get out of your
  pack to make yourself lighter.
• Use "swimming" motions, thrusting upward to try
  to stay near the surface of the snow.
• Above all, do not panic. Keeping your breathing
  steady will help preserve your air space and
  extend your survival chances. If you remain calm,
  your body will be better able to conserve energy.

• When the avalanche comes to a stop try and and
  dig your way up to the surface if you know you
  are close.

• If you are in over your head (not near the
  surface), try to maintain an air pocket in front
  of your face using your hands and arms, punching
  into the snow.

14
Tips on Avalanches

• If you are in an area that is highly at risk
  for avalanches be sure not to ski or use any
  snowmobiles on the mountain.
• Try not to use any explosives around an
  avalanche zone.

• If there was a heavy snow fall the night before
  make sure not to go on the mountain because you
  might trigger an avalanche.
• Dont ever go alone on a mountain that has been
  known to have avalanches.

15
How to prevent Avalanches
To prevent avalanches they build up snow fences
to prevent buildup of snow in the starting-zones.
Also defecting walls are built up to divert
avalanche flows away from buildings and even
entire towns. Sheds are also build across
roadways that pass through persistent avalanche
paths and they can help to protect motorists from
avalanches. Slopes with trees help to prevent
avalanches as well. They use explosives to set
off small avalanches in areas that are of
potential danger. This is to reduce the size of
future avalanches in the risk area.
16
Warning for Avalanches

• There isn't really such thing as an avalanche
  warning because you cant give a warning for an
  avalanche. Avalanches dont happen over a period
  of time like other natural hazards do. They
  happen because of vibrations and heavy snow fall
  so you cant really say when they are going to
  happen until they actually do.

17
Future Research

• They are doing research to find out about the
  mechanisms that govern the build-up of snow -
  wind and precipitation - instability within the
  snow cover, and the flow of avalanches.
• The main objective of this research is to improve
  zoning and make defences more effective and more
  reliable.

18
Pictures
19
Avalanche Dog

• This is an avalanche dog.
• Avalanche dogs are used after an avalanche has
  occurred. They sniff through the snow to try and
  find any people that might be buried underneath.

20
Bibliography
Internet http//europa.eu.int/comm/research/succes
s/en/env/0338e.html. http//geography.about.com/li
brary/weekly/aa022299.htm http//nsidc.org/snow/av
alanche/ http//www.climbersguide.com/training/ava
lanche.html http//www.cln.org/themes/avalanches.h
tml
http//www.csac.org/Incidents/2002-03/20030307-Ind
ia.html http//www.geo.mtu.edu/department/classes/
ge404/avalanche/control.html http//www.natives.co
.uk/news/2002/1202/12aval.htm