Storms and Cyclones

Storms

A storm that has both thunder and lighting is called a thunderstorm.

It is a violent weather condition of heavy rainfall and high speed winds.

Introduction to Thunderstorm

Thunderstorms develop in hot, humid tropical areas like India very frequently. The rising temperatures produce strong upward rising winds. These winds carry water droplets upwards,

where they freeze, and fall down again. The swift movement of the falling water

droplets along with the rising air create lightning and sound.

It is this event that we call a thunderstorm.

Conditions that lead to Thunderstorm

Tornado is an extremely strong and dangerous wind that blows in a circle.

It proceeds in a rotating column and extends form the surface of the Earth to a thundercloud.

A tornado is a dark funnel shaped cloud that reaches from the sky to the ground

Introduction to Tornado

Cyclones

A violent storm with very strong winds which move in a circle is called a cyclone.

A severe form of thunderstorm leads to a cyclone .

Introduction to Cyclones

Before cloud formation, water takesup heat from the atmosphere to changeinto vapour. When water vapour changesback to liquid form as raindrops, thisheat is released to the atmosphere. Theheat released to the atmosphere warmsthe air around. The air tends to rise andcauses a drop in pressure. More airrushes to the centre of the storm. Thiscycle is repeated. The chain of eventsends with the formation of a verylow-pressure system with veryhigh-speed winds revolving around it.It is this weather condition that we calla cyclone. Factors like wind speed,wind direction, temperature andhumidity contribute to the developmentof cyclones.

Conditions that lead to Cyclone

At approximately 11 pm local time, 13 April 2010, a severe storm struck parts of Bangladesh and eastern India. It lasted about 90 minutes, with the most intense portion spanning 30–40 minutes. Over 91,000 dwellings were destroyed in India and several thousand in Bangladesh.

According to local officials the storm was an extreme northwestern commonly formed over the Bay of Bengal during the hot months of the year. The cool air in the clouds was met by hot air rising from the ground, which caused the storm to start rotating. Although thunderstorms had been predicted, the severity of the storm was unexpected.

The storm struck in northeastern parts of West Bengal and Bihar states, with winds estimated from 120–160 kilometers/hour (75–100 miles/hour), then moved into Bangladesh. The strong winds uprooted trees, displaced roof tops, and snapped telephone and electricity lines. Power was lost throughout the area, and communication was difficult due to severed phone lines and damaged rail lines. Nepal, which relies on India for part of its power generation, was also affected by the outages. The initial strong winds were followed by heavy rains, causing further damage to weakened structures. Widespread damage to crops and livestock was also reported in both West Bengal and Bihar, as well as in Bangladesh. More than 8,000 hectares of maize was destroyed in West Bengal. More than 4,000 hectares of maize . In Assam, paddy crops, bananas, and other vegetation were damaged. Assam crops were already in poor shape due to earlier hail storms before 13 April storm, and were further damaged by another strong storm on 15 April.

Case Study – Cyclone that hit Bihar, West Bengal and Assam on April 14, 2014

In Bihar, storm victims are being given rice, cash, and asbestos sheets to rebuild their houses. Families of the deceased are also receiving money to pay for last rites plus an ex gratia payment of Rs 150,000 from the Chief Minister's Relief Fund. Phone service was restored to most of the region after 30 hours without service, However, areas near the Nepal-India border remained without power on 17 April. On 20 April, the Bihar Electricity Board said that it would be at least a month to repair all damaged electrical transmission towers. Rolling blackouts were conducted in Nepal to combat the decreased electricity availabilityIn West Bengal, Civil Defense Minister Srikumar Mukherjee is personally overseeing rescue efforts. As of 15 April, all major roads and rail lines were cleared and power had been restored to 50% of the population. However, some of the hardest hit towns had not yet received any government aid by 16 April, causing widespread anger. Mukherjee admit state government was struggling to distribute food rations, blaming insufficient manpower for the delay.In Assam, food and building supplies have been distributed to storm victims."We have taken all possible measures to provide relief and other financial assistance to people hit by the storm," remarked Relief and Rehabilitation minister Bhumidhar Barman. An ex gratia payment of Rs 5,000 was announced for the next of kin of storm victims, plus Rs 300,000 to be released at a later date.

Difference between Storm and Cyclone Storm A storm is bad weather

with precipitation. Storm is a violent

disturbance of the atmosphere with strong winds and usually rain, thunder, lightning, or snow.

Cyclone A cyclone is any low

pressure. Cyclone is a system of

winds rotating inwards to an area of low barometric pressure, with an anticlockwise (northern hemisphere) or clockwise (southern hemisphere) circulation; a depression.

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