Natural Disaster Early Warning Systems
By Lindsay Jackson
ÃÂÃ ÃÂÃ ÃÂÃ ÃÂÃ ÃÂÃ ÃÂÃ ÃÂÃ ÃÂÃ Experts can recognise the conditions that lead to avalanches by studying terrain, snow and weather in an area; they can predict tornados and hurricanes 12 to 24 hours in advance. The problem is, many developing countries do not have an early warning system in place, and many people do not know the signs that a natural disaster is about to occur.
By definition, an avalanche is a mass of snow that slides down a mountain slope. Most avalanches result from weather conditions that cause snow on a mountain slope to be come unstable. Heavy winds, explosions, skiers and earth tremors may cause avalanches. There are four main factors involved in the event of an avalanche (1) a steep slope (normally between 25 and 50 degrees), (2) a snow cover, (3) a week layer in the snow cover, and (4) a trigger.
See appendix 1.
Experts have many ways of reducing the amount of avalanches that occur, for example, planting trees and using explosives to decrease the amount of snow. But enviably, every year, so many avalanches occur that it is very difficult to make statistics, and many avalanches are not even recorded; on average 200 people are killed per year.
Preparation, recognising avalanche terrain, being able to asses snow stability and search and rescue techniques are key in reducing the amount of fatalities, and increasing safety when backcountry skiing, snowboarding or climbing. When backcountry skiing, it is vital to have a transceiver and a shovel.
Because of the amount of fatalities avalanches cause, many countries have developed an early warning system, in which experts issue a colour from green (low) to deep red (extreme). See appendix 2.
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