Avalanche

• Avalanche refers to a mass of snow, ice, and rocks transferring hastily down a steep slope
• Avalanches happen in many formats and sizes, i.e., transferring unfastened snow to the displacement of vast slabs of snow. Slab Avalanche is far more damaging than unfastened snow displacement as it’s able to destroy forests and small villages in its course. Proper prediction and protective measures must be taken
• Avalanches are classified into two types: slab avalanches, which are built of tightly packed snow and are caused by the collapse of an underlying weak snow layer, and loose snow avalanches, which are composed of looser snow
• Avalanches often speed quickly after being triggered and develop in mass and volume as they gather additional snow. If an avalanche travels quickly enough, part of the snow may combine with the air, resulting in a powder snow avalanche
• Avalanches are separate from slush flows, mudslides, rock slides, and serac collapses, despite their apparent similarities. They are also distinct from large-scale ice movements
• Avalanches may occur in any mountain range with a persistent snowfall. They are most common in the winter and spring, although they may occur at any time of year. Avalanches are one of the most dangerous natural risks to life and property in mountainous places, hence tremendous efforts are undertaken to manage them
• There are several categorization systems for various types of avalanches, which vary depending on the demands of their users. Avalanches are classified based on their magnitude, destructive capacity, mode of start, composition, and dynamics

Features of avalanches:

•  3 principal components of avalanches include the beginning zone, the avalanche track, and the runout zone. Avalanches release from the beginning zone. That’s usually the riskiest part of the slope and typically better at the mountain
• Once the avalanche begins to slide, it passes down the avalanche track, the gravitational route it follows downhill. After avalanches, massive clearings or lacking chutes of bushes offer clues to an avalanche’s trajectory
• An avalanche is then stopped at the lowest point of a slope, inside the runout zone, where snow and particles build up

Factors responsible for Avalanche:

• Heavy Snowfall: It deposits snow in risky regions and places stress at the susceptible layer of snow, inflicting Avalanche
• Human Activity: Winter sports activities that require steep slopes input stress at the layer of snow inflicting Avalanche
• Wind Direction: The winding path determines snow accumulation at the mountain slopes
• Steep Slopes: An avalanche is likewise because of the impact of gravity
• Warm Temperatures: The snowpack melting, and the gathered snow may be fluid
• Layers of Snow: There are situations wherein snow is already in the mountains and has become ice. Then, sparkling snow falls on a pinnacle that can, without difficulty, slide down
• Earthquake: It generates seismic waves that cause the floor to vibrate, and matched with the gravitational pull, it’s one of the fastest approaches to strike an Avalanche

These are the factors responsible for the avalanche.

We need proper planning for the prediction and preventive measures of avalanches.

Glacial Lake Outburst Flood (GLOF):

• A Glacial Lake Outburst Flood, or GLOF, is the rapid discharge of water from a lake fed by glacier melt that has developed at the glacier’s side, in front, under, beneath, or on its surface               
• GLOFs may inflict disastrous effects like flooding because of the launch of massive volumes of water in a short period

E.g., In 2021, parts of Uttarakhand witnessed tremendous flooding after a bit of the Nanda Devi                Glacier broke off at Joshimath in the Chamoli district of Uttarakhand. This resulted from improper Avalanche prevention structure and prediction and preventive measures.

NDMA pointers for GLOF:

Some prediction and preventive measures:

• Identifying and mapping the probably risky lakes via area observations, geomorphological and geotechnical characteristics, satellite TV for PC imagery, etc.
• We are using Synthetic Aperture Radar (SAR) imagery to come across adjustments in water bodies, new lake formations, etc
• Structural measures like pumping or siphoning out water, making tunnels via moraine barriers, decreasing the range of lake formations, etc
• We regulate land-use making plans and prohibit the development and infrastructure improvement in excessive threat zones
• We are setting up an early solid caution gadget and emergency reaction teams, schooling, cognizance of some nearby populace, etc

Conclusion

An avalanche (also known as a snow slide) is a fast-moving flow of snow down a slope, such as a hill or a mountain. Avalanches may occur spontaneously, as a result of variables such as excessive precipitation or a decreasing snowpack, or as a result of external sources such as people, animals, and earthquakes. Large avalanches, which are mostly made up of moving snow and air, have the power to catch and transport ice, rocks, and trees.