AVALANCHES

What?

Falling masses of snow that contain rocks, soil or ice that move downhill at speeds up to 300 kph.

When hazardous?

When interact with people & surrounding i.e. cause damaged to

properties, death, injuries,It also cause damaged to transport

networks & livelihood-tourism

TYPES

WET SNOW AVALANCHES

SLAB AVALANCHES

LOOSE SNOW AVALANCHES

-Later season-8 to 25 km/hr-causing snow weight 1 million tonne

-more deadly-start due to human error-a large slab ice & snow shear away from hillside & more rapidly downhill-it has immense power

-start at a single point-involve loose powdery snow-occur little warning-any season-speed; 300km/hrforce 50 tonnes/m2

CAUSES

HEAVY SNOWFALL TREE REMOVEDHIGH RAINFALLHUMAN

RISE IN TEMPERATURE

Add weight easily snowfalls

Rapid melting of snow, in

spring

Off piste skiing

Lubricate snow & trigger avalanches

Snow move downhill

unimpeded

Ways to reduce

Closing Avalanches prone slope & issue

warning

Trigger small avalanches

Controlled Avalanches activities

Planning

-Restrict activities; snowboarding, skiing in recreation with high risk areas.

-close prone slope & issue warning depend:snow condition,

Under controlled condition before the snow pack build to a dangerous situation. (use of explosive to produce small avalanches)

Stabilizing snow pack in starting zone-prevent snow pack from achieving momentum to begin to move2.planting of trees

Where and when to build infrastructure in mt areas to minimized damage to building & infrastructure. It is based on record of previous avalanches

Case study: Galtur Austria.Where? Tyrolean village of GalturWhen? Tues, 23 Fe, 1999, 4 pmCauses:-Jan 20 Jan onwards, a sequence of 3 storms recorded-Warmer weather at end of Jan causes melting & re-freezing until there was a much greater accumulation of snow-Temperatures had fluctuated so that heavy wet snow fell on top of dry snow, forming unstable boundaries in the snow packNature of avalanches:100 m height, 800 m wide, 2 sources; 200 kmph -300 kmph, 400 000 tonnes & lasted 16 seconds

Effect:

People crushed to death, 30 died in event, by 27th

Feb -38 final death toll,40 000 were stranded in ski resort, cars were crushed & hurled across roads, housesWere completely buried, snow & ice clearly sliced off top of one building.

CASE STUDY: GALTUR AUSTRIA

Where? Tyrolean village of Galtur

When? Tues, 23 Fe, 1999, 4 pm

Causes:1. Jan 20 Jan onwards, a sequence of 3 storms recorded2. Warmer weather at end of Jan causes melting & re-freezing until there was a much greater accumulation of snow3. Temperatures had fluctuated so that heavy wet snow fell on top of dry snow, forming unstable boundaries in the

snow pack

-Restrict activities; snowboarding, skiing in recreation with high risk areas.

-close prone slope & issue warning depend:snow condition,

Under controlled condition before the snow pack build to a dangerous situation. (use of explosive to produce small avalanches)

Stabilizing snow pack in starting zone-prevent snow pack from achieving momentum to begin to move2.planting of trees

Where and when to build infrastructure in mt areas to minimized damage to building & infrastructure. It is based on record of previous avalanches

Nature of avalanches:100 m height, 800 m wide, 2 sources; 200 kmph -300 kmph, 400 000 tonnes & lasted 16 seconds

Effect:People crushed to death, 30 died in event, by 27th Feb -38 final death toll,40 000 were stranded in ski resort, cars were crushed & hurled across roads, housesWere completely buried, snow & ice clearly sliced off top of one building.