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Avalanches: Causes, types, risks, tips to follow during snowy cascades

This year has already seen an unfortunate share of avalanches and now JKDMA has warn for more in coming days; here's what to know about avalanches and safety measures that can be taken if one is stuck

Avalanche-hit Uttarakhand

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Swati Gandhi New Delhi
The Jammu and Kashmir Disaster Management Authority Wednesday issued avalanche warnings in six districts of the Union territory, officials said. Avalanche with low danger level is likely to occur 3,000 to 3,500 metres above the sea level over Doda, Kishtwar, Poonch, Ramban and Baramulla districts in the next 24 hours, the officials of the Authority said. Another avalanche with medium danger level is likely to occur above 2,800 metres over Ganderbal district in the next 24 hours, they said.

On April 15, an avalanche struck near Zojila Pass in Ladakh. While there has been no loss of life, this is the second such incident that took place in a span of just 15 days. On April 4, seven tourists were killed while 23 others were injured after a massive avalanche struck Sikkim's Nathula region.

Amid increasing incidents of avalanches in the country, here is what you should know about causes and types of avalanches and safety measures that can be taken to prevent mishaps:

What is an avalanche?

According to National Geographic, an avalanche is a mass of snow, soil or rock that tumbles down a mountain. While avalanches of rocks or soil are known as landslides, a snow avalanche is where an unstable mass of snow breaks away from a slope. It is the most common kind of avalanche and one that can sweep downhill "faster than the fastest skier", as per National Geographic experts.

How does an avalanche occur?

An avalanche occurs after layers in the snowpack weaken. Snowpack refers to layers of snow that are built up in a region. In the winter, the snowpack becomes thick due to the repeated snowfalls in the region. They are most likely to occur after an area receives fresh snowfall, which adds a new layer to the snowpack. According to United Nations' Intergovernmental Panel on Climate Change (IPCC), snow avalanches can occur either spontaneously because of meteorological factors or can be triggered by the passage of the people in an avalanche terrain.

Types of snow avalanches

There are two types of snow avalanches-

Sluff avalanche: It occurs when the snowpack's weak layer is on top. This type of avalanche occurs in large numbers but it is less dangerous than slab avalanches.

Slab avalanche: It occurs when the weak layer lies lower in a snowpack. This layer is also covered with other layers of compressed snow, which breaks off when an avalanche is triggered. Such avalanches occur infrequently but can cause most of the damage. Slab avalanches can run for many kilometres and result in massive destruction, according to National Disaster Management Authority.

Climate change and its impact on avalanche

According to Dr Miriam Jackson, the programme coordinator at International Centre for Integrated Mountain Development (ICIMOD), "There is evidence that climate change has increased the frequency and intensity of avalanches. There is reported increased avalanche activity in some slopes of the Western Indian Himalaya over the past decades related to increased frequency of wet-snow conditions."

Jackson further added, "If avalanches are occurring in different places than before, this is a problem. changes in temperature (swings between high and low temperature) and changes in wind pattern can affect avalanche occurrence, however. Also, there is some evidence of more intense snowfall events (as seen in North America recently) and this increases the likelihood of avalanches as well as their size. In some areas (e.g. Norway) there is increased activity in the mountains such as ski touring and ski mountaineering (partly due to better equipment so what was accessible to only a few people before is now accessible to many), and so more people are at risk for avalanches."

How to protect yourself from an avalanche

According to Dr Jackson, "The safest thing to do is to avoid them. In some countries, there are avalanche warnings, which should be followed strictly. Many people that spend lots of time in the mountains learn how to dig a shallow pit and study the snowpack to see if it's unstable. Also, if you see any signs of fresh avalanche activity then that's a very good indication that more avalanches may occur. Also, if spending lots of time in the mountains, many people use tracker beacons so that if they are buried in an avalanche, then they can be found more easily (you set the gear to transmit while you are walking/climbing/skiing and if one person is taken in an avalanche, the others in the group will set their equipment to find)."

It is one of the most common tools that is used by rescuers to find victims. "Avalanche beacons are beepers that emit consistent noise when activated. Beacons can help rescuers locate a buried victim more than 80 meters (262 feet) away", according to a National Geographic report.

For those who are stuck in an avalanche, Dr Jackson advises to "keep the mouth closed, try to hold onto something solid (tree etc) or if near the top of the avalanche, try and get to the side of it and away from the centre. If you are stuck n the middle, try and make a swimming motion to keep near the top of the snowpack. When it stops, try and put your hand up out of the snow and try and clear an area around your face to breathe. Conserve your air and energy."

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First Published: Apr 20 2023 | 5:13 PM IST

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