Model Answer

A thunderstorm forms when three key ingredients are present: moisture, rising unstable air, and a lifting mechanism. The sun heats the Earth’s surface, causing the air above it to warm and rise. As this warm air rises, it carries water vapor upwards. The rising air cools, and the moisture condenses, forming clouds. As the storm grows, the cloud extends into cooler, freezing layers of the atmosphere, where ice particles are created. These ice particles collide, generating electric charges, which build up and cause lightning. The lightning creates sound waves, which we hear as thunder.

Stages in the Lifecycle of a Thunderstorm

1. Developing Stage: In this stage, warm air rises, forming a cumulus cloud that grows into a towering shape as the updraft continues. This stage generally has little to no rain and occasional lightning.
2. Mature Stage: The thunderstorm reaches its peak when the updraft feeds the storm and precipitation begins to fall. This creates a downdraft. The downdraft and cool air at the surface form a gust front, which can lead to severe weather conditions like heavy rain, hail, strong winds, and sometimes tornadoes. This is the most intense phase of the storm.
3. Dissipating Stage: In the final stage, the gust front moves away from the storm, cutting off the warm, moist air that was sustaining it. Precipitation decreases, but lightning can continue. The storm gradually weakens.

Thunderstorms are most common during the summer months and typically occur in the afternoon and evening. Under the right conditions, they can lead to flash floods due to the intense rainfall.

Model Answer

The Fujiwhara effect refers to the interaction between two cyclones or hurricanes when they come close enough to spin around a common center, creating a dramatic and intense “dance” between them. This effect occurs when the cyclones are close enough to influence each other’s rotation. As per the National Weather Service (NWS), these cyclonic interactions are becoming more frequent, largely attributed to global warming, which heats ocean waters and enhances cyclone activity.

Implications of the Increasing Occurrence of the Fujiwhara Effect on Coastal Regions

1. Damage to Infrastructure: The Fujiwhara effect can cause significant damage to coastal infrastructure due to powerful winds, storm surges, and flooding. For example, in 2021, the interaction between Cyclone Seroja and Cyclone Odette in the Indian Ocean led to widespread infrastructure damage in Australia.
2. Threat to Life: Stronger storms resulting from the Fujiwhara effect bring more powerful winds, heavier rainfall, and larger storm surges, increasing the risk of fatalities. The 2022 Fujiwhara interaction of Typhoon Hinnamnor and Tropical Storm Gardo in the western Pacific Ocean resulted in fatalities in South Korea, primarily from drowning.
3. Loss of Livelihood: In rare cases, when two cyclones merge, they can form a mega-cyclone capable of devastating coastal economies, especially in agriculture and tourism. For instance, Superstorm Sandy impacted the livelihoods of many people in the U.S. due to its storm surges and extensive flooding.
4. Ecosystem Disruption: The Fujiwhara effect can also disrupt coastal ecosystems by causing stronger winds and larger waves, leading to physical damage to mangrove forests, coral reefs, and estuary habitats, all of which are crucial to the local biodiversity and economy.
5. Forced Migration: The increasing frequency of the Fujiwhara effect could lead to forced migration in vulnerable coastal areas, contributing to internal migration challenges and overwhelming local infrastructure.

Given its unpredictable nature, it is essential to enhance disaster preparedness and develop effective early warning systems to mitigate risks associated with the Fujiwhara effect.

Model Answer

Volcanoes are shaped and their explosive nature is determined largely by the type of magma involved in their formation. The composition of magma, including its viscosity and gas content, plays a crucial role in both the volcano’s shape and how violently it erupts.

1. Basic Lava and Shield Volcanoes

Basic lava, which is rich in iron and magnesium but low in silica, is highly fluid and flows easily. This type of lava is typically dark in color, such as basalt, and has a lower viscosity, allowing it to travel long distances before solidifying. Due to its fluid nature, it leads to the formation of shield volcanoes, which have broad, gently sloping sides. These volcanoes are less explosive because the lava can flow easily, allowing gas to escape gradually. An example of a shield volcano is the Big Island of Hawaii, which has been formed by the consistent outpouring of basic lava.

2. Acid Lava and Composite Volcanoes

Acid lava, in contrast, is rich in silica, making it more viscous and harder for gas to escape. This leads to a build-up of pressure, which results in explosive eruptions. Acid lava tends to solidify quickly and does not travel far, leading to the formation of steeper, conical-shaped volcanoes known as composite volcanoes. These volcanoes are typically characterized by alternating layers of solidified lava and pyroclastic material. Examples include Mount Fuji in Japan, Mount Rainier in the U.S., and Mayon Volcano in the Philippines. The high viscosity of the magma often causes eruptions to be violent, with eruptions creating loud explosions and even forming calderas—large depressions that can result when a volcano collapses after an explosive eruption. Notable calderas include the Yellowstone Caldera in Wyoming and Long Valley Caldera in California.

3. Viscosity and Explosiveness

In general, the higher the viscosity of the magma, the more explosive the eruption. This is because thicker magma traps gases, increasing pressure until it is released explosively. Therefore, while basic lava leads to non-explosive eruptions, acid lava results in some of the most explosive volcanic activity on Earth.