Black Carbon
Black carbon is a major component of fine particulate matter (PM2.5) and a potent short-lived climate pollutant.
It is produced by the incomplete combustion of fossil fuels (especially diesel and marine heavy fuel oil), biofuels and biomass.
It has a warming impact nearly 1,600 times stronger than carbon dioxide over a 20-year period.
Unlike CO₂, it does not remain long in the atmosphere (typically 4–12 days), but its immediate impact is intense, especially in polar regions.
Avalanches
Avalanches are common natural as well as man-made disasters common in mountainous regions. During an avalanche, a mass of snow, rock, ice, soil, and other material slides swiftly down a mountainside. It can cause heavy causalities and change the geography of the region substantially.
About
Avalanches occur when an unstable mass of snow breaks away from a mountain slope. As it descends, it gathers more snow, ice, and debris, turning into a powerful force capable of destruction.
Types
Snow Avalanches: These include sluff (small slides of dry, powdery snow) and slab avalanches (large, cohesive slabs of snow that break off and slide down).
Rock Avalanches: Consist of massive chunks of rock breaking off and sliding down steep slopes.
Ice Avalanches: Common around glaciers, where large ice masses break off and slide down slopes.
Debris Avalanches: Contain soil, loose stones and a mix of materials that move downhill with force.
Causes
Causes
Avalanches occur as layers in a snowpack slide off.
A snowpack is simply layers of snow that build up in an area, such as the side of a mountain.
In winter, repeated snowfalls build a snowpack dozens of meters thick.
The layers vary in thickness and texture, and the bonds between the layers of a snowpack may be weak.
There are numerous natural and man-made factors responsible for an avalanche.
Heavy Snowfall: When a high rate of snowfall occurs, it leads to snow accumulation on the mountain slopes. This triggers the weaker layer of snow in the snowpack of unstable areas of the mountain causing avalanches.
Wind Direction: The direction of the wind determines the patterns of the snowfall as well as snow accumulation on the mountain slopes.
Layering of Snow: The gradual snowfall creates a layer-by-layer accumulation of snow that creates a hypersensitive snowpack. A small trigger can cause these layers of snow to fall.
Steeper Slopes: An avalanche is also caused by the influence of gravity. If the snow gets accumulates on the slopes of the mountain, then it is prone to rush down the slopes at greater speeds.
High Temperatures: Temperature is one of the important factors for the avalanche because of high temperatures the surface layer of the snowpack gets melted. The accumulated snow will become highly susceptible to sliding down.
Earthquakes: It is one of the important factors that trigger the layer of accumulated snowpack because earthquakes generate seismic waves that cause the ground to vibrate.
Developmental activities: During the developmental activities, the terrain vehicles in regions with unstable layers of snow can dislodge the layers from the surface and cause them to slide down under gravity.
Deforestation: Clearing trees and forests causes the soil to become loose, hence during snowfall the ground does not have the strength to hold the heavy snow. This causes landslides or avalanches of rocks and soil.
Winter Sports Activities: At times, excessive pressure is transferred to snow layers during winter sports activities like skis and sledding. Excess of these activities can cause the topmost loose layer of snow to slip and eventually cause a greater catastrophe.
Mitigation
Avalanche Detection and Monitoring: Scientists analyze snowpack stability, wind patterns, and temperature variations to assess avalanche risks.
Structural Barriers: Diversion walls, fences and rakes help redirect or slow down snow masses.
Controlled Explosions: In ski resorts and high-risk zones, authorities use controlled explosions to trigger small avalanches before they become dangerous.
Reforestation and Vegetative Barriers: Trees and vegetation help stabilize slopes and reduce the chances of snow slides.
Early Warning Systems: Using advanced sensors and beacons, authorities can warn residents and workers in avalanche-prone areas.
Emergency Response Planning: Training personnel and equipping them with rescue tools, including avalanche beacons and probes, enhance survival chances during disasters.
Nature-based Solutions
NbS refers to actions to protect, sustainably manage and restore natural or modified ecosystems that address societal challenges (like climate change, food security and disaster risk) effectively and adaptively, simultaneously providing human well-being and biodiversity benefits.
Why Pakistan is Prone to Earthquakes?
The Earth's outer layer (the lithosphere) is not a single solid shell. Instead, it's made up of giant pieces called tectonic plates that slowly move over geological time.
In Pakistan's region, three major plates interact:
Indian Plate — moving northward.
Eurasian Plate — forming the massive Asian landmass.
Arabian Plate — contributing to the complex tectonics of the west and south.
Where these plates meet, great forces build up as they push, pull or slide past one another. When stress accumulates along cracks or fractures (called faults), the rocks suddenly snap back into a new position. This releases energy in the form of seismic waves — and that is what we feel as an earthquake.
Pakistan lies near one of the most tectonically active regions on Earth. The Himalayan Front and various fault systems through Balochistan and southern Pakistan mark zones where the plates interact. Movement along these faults builds up strain that eventually releases as earthquakes.
Western Disturbance
A Western Disturbance (WD) is an extra-tropical weather system that moves from west to east, bringing rain, snowfall, and storms to northern parts of the Indian subcontinent, especially during winter and early spring.
It originates over the Mediterranean region, Black Sea, or Caspian Sea.
It forms when cold polar air interacts with warmer, moist air, creating low-pressure systems.
These systems are carried eastward by westerly winds in the upper atmosphere, particularly the subtropical westerly jet stream.
While travelling, western disturbances accumulate moisture from surrounding seas.
When this moist air encounters the Himalayan mountains, or is forced upward due to temperature contrasts, it rises and cools.
Cooling leads to condensation, forming clouds that result in rainfall in plains and snowfall in higher altitudes.
Precipitation associated with Western Disturbances (WDs) influences Himalayan climate, glaciers, snow-water storage, flora, fauna, agricultural crops and human inhabitants, etc.
Winter rainfall from western disturbances is vital for rabi crops, especially wheat, Mustard, Barley. Adequate rainfall improves soil moisture, crop yield and food security.
