Rising Avalanche Risks

• 07 Mar 2025

For Prelims: Avalanche, Earthquake, Himalayas, Avalanche Monitoring Radar.  

For Mains: Causes of avalanches and ways to mitigate its risks. 

Source: HT 

Why in News? 

A massive avalanche occurred in Uttarakhand’s Chamoli district, burying people and properties under snow and debris. 

• Warmer temperatures, more rain, and less snowfall are altering snow conditions, increasing avalanches in the Himalayas. 

What is an Avalanche? 

• About: An avalanche is the rapid flow of snow, ice, and debris down a mountain slope. It often carries earth, rocks, and rubble, causing destruction. 
  • Avalanche risk peaks from December to April due to heavy winter snowfall (snow accumulation) and spring thaw (weakening snow layers). 

• Types: 
  • Loose Snow Avalanche: It starts from a single point where snow is not well bonded, spreads in an inverted V-shape as snow particles fall, and is less dangerous due to lower volume and speed. 
  • Slab Avalanche: It occurs when a cohesive snow slab breaks away from underlying layers, often reaching speeds of 50–100 km/h and causing significant destruction. 
  • Gliding Avalanche: The snowpack slides down a smooth surface, like grass or rock slabs, leaving a broad fracture line separating it from stationary snow. 
  • Wet-Snow Avalanche: A wet-snow avalanche is naturally triggered by rising temperatures or rain, as meltwater weakens the snow layer bonds.

What are the Causes of Avalanche? 

Natural 

• Snow Accumulation: Continuous or excessive snowfall increases the weight of the snowpack, leading to instability. E.g., Himachal Pradesh avalanche (January 2020). 
  • Windy conditions on fresh snow slopes can enhance instability. 
• Weak Snow Layers: Temperature changes weaken the snowpack, e.g., fresh snow over a weak base may lead to an avalanche. 
  • Sudden warming weakens the snowpack, leading to wet-snow avalanches. 
• Earthquakes: Seismic activity can destabilize snow layers. E.g., Nepal earthquake 2015 triggered avalanches in the Langtang Valley, Nepal. 

Human-Induced 

• Deforestation: Tree roots stabilize slopes, but deforestation, like in Himalayan road projects, raises avalanche and landslide risks. 
• Adventure Tourism: Skiing, snowboarding, and mountaineering can trigger avalanches by disturbing the snowpack. E.g., In February 2024, skiers in Gulmarg triggered an avalanche by skiing in a non-ski zone.  
• Global Warming: Rising global temperatures cause frequent freeze-thaw cycles, increasing avalanche risks. 

How Avalanche Differ from Landslides? 

Basis	Avalanche	Landslide
Definition	A type of landslide that occurs in snowy regions, involving the movement of snow and air.	A form of mass wasting where a large area of land moves under the force of gravity.
Causes	Heavy snowfall, Unstable snowpack, ice pellets, Strong winds depositing snow on slopes, Temperature fluctuations	Earthquakes, Volcanic eruptions, Heavy rains and floods, Deforestation, Wildfires
Flowing Matter	Composed of snow and air.	Consists of soil, rocks, or mud.
Occurrence	Occurs in snowy regions where snowpacks are weakly held by snow layers.	Happens on land with steep slopes.
Speed of Movement	Very fast (up to 250 miles per hour in extreme cases)	Can be fast like avalanches or slow-moving over time

Why are Himalayas More Prone to Avalanches? 

• Rising Temperatures: The Himalayas are warming faster than average, causing glacier melt and retreating snow lines.  
  • Avalanches in the western Himalayas have increased significantly since the 1970s. 
• Wetter Snow: Warmer temperatures cause rain instead of snow, making the snowpack wetter and unstable. 
  • Rainwater percolating into the snowpack weakens its structure, reducing friction between snow layers and increasing avalanche risks.  
• Permafrost Melting: The melting of permafrost causes water accumulation at their base, making ice layers more prone to sliding. 
• Increased Wind Speeds: Rising temperatures are causing higher wind speeds, which increase snow transport and make fresh snow layers more unstable. 
• Steep Slopes: The steep and rugged terrain of the Himalayas makes it easier for snow to slide down due to gravity. 
• Earthquakes: The Himalayas lie in a seismically active zone, and earthquakes can trigger avalanches by shaking the unstable snow layers.

Karakoram Anomaly 

• The Karakoram Anomaly refers to the unusual behavior of glaciers in the Karakoram Range, where they have either remained stable or experienced slight mass gains, contrary to the widespread trend of glacier retreat observed globally due to climate change. 
  • Karakoram Range is a mountainous region spanning Pakistan, India, Afghanistan, Tajikistan, and China. 

How to Mitigate Avalanche Risk? 

• Early Warning Systems (EWS): EWS can reduce avalanche risk by monitoring snow conditions (using sensors and satellites), issuing alerts (weak snow layers), and aiding rescue efforts (timely preventive action). 
  • E.g., In 2022, India’s first avalanche monitoring radar was installed in Sikkim that can detect avalanches within 3 seconds of trigger. 
• Snow Test: Snow tests can be conducted regularly to assess the stability of the snowpack and predict avalanche risks.  
• Defensive Structures: Snow sheds can be constructed over transportation routes to shield vehicles from falling snow. 
  • Wall reinforcement and splitting wedge can help strengthen structures and deflect avalanches away from buildings. 
• Dual-Purpose Infrastructure: Build dams to protect against flooding and debris flows after snowmelt, ensuring year-round disaster mitigation. 
• Artificial Avalanche Triggering: Controlled explosions trigger small avalanches to prevent larger ones, protecting roads, settlements, and ski slopes. 
• Afforestation: Encouraging forest growth can help in natural avalanche control over time. 

Conclusion 

Global warming and climate change are intensifying avalanches in the Himalayas by altering snowpack stability, increasing rainfall, and accelerating glacier melt. With the region's steep terrain and seismic activity, proactive measures such as early warning systems, protective infrastructure, and controlled avalanche triggering are essential to mitigate risks and safeguard communities. 

Drishti Mains Question:

Discuss how climate change is increasing avalanche risks in the Himalayas and suggest mitigation strategies.

UPSC Civil Services Examination, Previous Year Question (PYQ) 

Mains

Q. Bring out the relationship between the shrinking Himalayan glaciers and the symptoms of climate change in the Indian subcontinent.  (2014)