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. As of 16 April, more than 140 deaths have been reported. At least 91 people died in the Indian state of Bihar, 44 in West Bengal, and 4 in Assam. In Bangladesh, five deaths and two hundred injuries were reported. Most of the deaths were women and children crushed when their huts were destroyed. Over 91,000 dwellings were destroyed in India and several thousand in Bangladesh; approximately 300,000 dwellings were at least partially damaged. Both mud and pucca housing were damaged by the storm. Nearly 500,000 people were left homeless or otherwise affected by the storm.
According to local officials, the storm was an extreme nor ‘ester commonly formed over the Bay of Bengal during the hot months of the year. Meteorologist S.I. Laskar said the storm was due to an unstable atmosphere caused by excessive heat and humidity. “It is quite normal in the pre-monsoon season,” he added. The severity of the storm was likely due to wind pulling the moisture from the Bay of Bengal northward to north Bihar, where it converged with another cloud formation to form a 20 km tall cloud mass. 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.
Although not a tropical cyclone, the storm brought back memories of Cyclone Aila, which killed 155 people in the same area in May 2009. One eyewitness described the storm: “It was all dark. I thought it was the end of the world and we were going to die.” Locals received no warning of the impending storm and were mostly sleeping when the storm hit, increasing the casualties. Out-dated equipment with limited capabilities was blamed for the lack of warnings.
The storm spawned a large tornado, which lasted about 20 minutes. It was the first tornado recorded in Bihar history. Tornadoes are a very rare occurrence in India – the last one was in 1998. Radar equipment which could have provided early warning had arrived in the area but had not yet been installed because the building to house it was still under construction. The storm occurred during a heat wave with temperatures greater than 40 °C (104 °F) reported. West Bengal regional weather office director Gokul Chandra Debnath said that the heatwave “could have been a catalyst … that triggered the tornado”. The amount of damage caused directly by the tornado is unknown.
The storm struck in northeastern parts of West Bengal and Bihar states, with winds estimated at 120–160 kilometers/hour (75–100 miles/hour), and then moved into Bangladesh. The strong winds uprooted trees, displaced rooftops, and snapped telephone and electricity lines. The worst damage was reported in the towns of Hemtabad, Islampur, Kaliaganj, Karandighi, and Raiganj. Purina had the most reported casualties. 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.
In Araria district, a jail was partially destroyed causing the transfer of 600+ inmates to another facility. In Rangpur, a police officer was killed and five others injured when a wall of the Rangpur Police Line building collapsed. The police barracks in Raiganj, which houses 300 officers, were partially destroyed. Several other police buildings had their roofs blown away.
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 and boro was destroyed in Bangladesh. 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.
Rescue efforts have been inhibited as many roads, including National Highway 34, are blocked by downed trees and telephone poles. Medical personnel and supplies were quickly rushed to the affected areas, and aid packages were announced. Aid workers began to distribute rice, dried fruits, water, and temporary tarpaulin shelters on 15 April. However, many remote regions remained inaccessible as of 16 April. Aid workers said that hundreds of thousands of victims had not received any relief by 16 April. Another rainstorm on 15 April added to frustrations.
On 16 April, Prime Minister Manmohan Singh announced an ex gratia payment Rs 100,000 to the next of kin to persons killed in the storm. The money will come from the Prime Minister’s National Relief Fund. In the Lok Sabha, members have taken turns blaming each other’s political parties for the delays. On 19 April, The Communist Party of India (Marxist) (CPM) asked for the central assistance of Rs 10 billion for Bihar and Rs 5 billion for West Bengal. Prashanta Mazumdar additionally asked for government workers to assess the damage and distribute relief. Indian National Congress (INC) member Deepa Dasmunshi countered by saying the state administration had failed miserably. All India Trinamool Congress (AITC) leader Sudip Bandopadhyay agreed and added that the CPM was “more involved in state terrorism” against political opponents than the distribution of aid. The CPM responded that West Bengal had done its best to provide relief. Dasmunshi strongly disagreed, claiming “not even one tarpaulin or piece of cloth has reached the victims. The state government has failed.” The CPM and other left parties accused Dasmunshi and Bandopadhyay of “playing politics at the cost of human lives”. Janata Dal (United) leader Sharad Yadav demanded that the House have a more thorough discussion on the matter