News Highlight
Seven dead, 27 rescued after avalanche hits Sikkim’s Nathu La.
Key Takeaway
- Seven persons were murdered, and 20 others were rescued after an avalanche hit five or six trucks with 20-30 tourists near Nathu La in East Sikkim.
- At MS-15, a large avalanche struck the Gangtok-Nathu La route (between Mile 13 and Mile 17).
- Five to six vehicles and 20-30 tourists going to Nathu La are believed to have become stuck in the snow.
- So far, 27 people have been rescued and sent to a nearby Army medical centre.
Avalanche
- About
- A mass of snow, rock, ice, soil, and other debris flows down a mountainside during an avalanche.
- Landslides are often used to describe avalanches of boulders or earth.
- The most common type of avalanche is a snow slide, which can sweep downhill faster than the fastest skier.
- When an unstable mass of snow breaks away from a slope, a snow avalanche occurs.
- Avalanches develop when layers of snow slide off.
- A snowpack is simply the accumulation of layers of snow in a certain place, such as the slope of a mountain.
Types of Avalanches
- Slab avalanches
- A slab avalanche occurs when the weak layer is lower in a snowpack. Several layers of compressed snow overlay this layer.
- When the avalanche occurs, the weak layer separates, dragging all the layers above it down the hill.
- Some pieces from a moving cloud of frozen particles in the air.
- Slab avalanches pose a risk to skiers, snowboarders, mountaineers, and hikers due to their thickness and speed.
- By far, slab avalanches are the most dangerous types for individuals.
- A slab can travel up to 130 km/h downhill, beginning as a coherent unit and then shattering into smaller fragments as it descends.
- Loose snow avalanches
- Loose snow avalanches occur as poorly connected surface snow slides downhill under its weight.
- They are commonly found on steep hillsides after a fresh snowfall.
- The snowpack is not very substantial because it has not had time to settle completely or has been turned loose by sunlight.
- Avalanches of this type have a single point of origin from which they spread as they go down the hill.
- These avalanches, or sluffs, are normally smaller and less deadly than slab avalanches.
- Although they can still be dangerous in the wrong terrain.
- Cornices
- Cornices are wind-deposited snow masses from steep topographical features such as ridges or summits.
- These stunning constructions can be lethal, falling off in response to changing weather conditions or a person’s or equipment’s weight.
- As they fail, massive amounts of snowfall down the slope below, causing an avalanche or maybe sparking a larger avalanche.
Causes of Avalanches
- Heavy Snowfall
- The first is heavy snowfall, which deposits snow in vulnerable regions and exerts strain on the snowpack.
- Summer precipitation is the most common source of wet snow avalanches.
- Human Activity
- Several avalanches have been started by humans in recent years.
- Winter sports that demand steep slopes frequently inflict stress on the snowpack, which it cannot handle.
- When combined with significant deforestation and soil erosion in mountain regions, the snow has limited stability during winter.
- Natural Causes
- They include earthquakes and tremors, which can frequently cause fissures in the snowpack.
- Fresh snow or rain can cause built-up snow to thaw and tumble down a mountainside.
- Avalanches have been reported to occur as a result of animal movement.
- Layers of Snow
- There are instances where snow has already accumulated in the mountains and has solidified into ice.
- Then new snow falls on top, making it easy to slide down.
- Warm Temperature
- Warm temperatures that linger for several hours per day might damage some of the upper layers of snow, causing it to slip down.
Why have the Himalayas become prone to Avalanches?
- The climate in the massive yet delicate snow-covered Himalayas has been swiftly shifting.
- Researchers discovered that winter temperatures in the northern Himalayas had risen by 0.65 degrees Celsius on average since 1991.
- It is greater than the global average rise of 0.44 degrees.
- Total winter precipitation has increased during this period, with more rain and less snowfall.
- Since 1970, rising temperatures have increased the frequency of avalanches, posing a threat to the route that provides access to the recently built Rohtang tunnel.
Conclusion
- A snow slide (also known as an avalanche) is a fast-moving snow flow down a slope, such as a hill or a mountain.
- Avalanches can develop naturally due to excessive precipitation or a diminishing snowpack.
- Because of external factors such as people, animals, and earthquakes.
- Avalanches have the ability to capture and move ice, rocks, and trees since they are largely made up of flowing snow and air.
Pic Courtesy: NY Times
Content Source: The Hindu