Cyclone Aila

Severe Cyclonic Storm Aila (JTWC designation: 02B) was the second named tropical cyclone of the 2009 North Indian Ocean cyclone season. Warned by both the Regional Specialized Meteorological Center (RMSC) and Joint Typhoon Warning Center (JTWC), Aila formed over a disturbance over the Bay of Bengal on May 23, 2009 and started to intensify and organize reaching sustained wind speeds of 110 kmh (70 mph). It was the worst natural disaster to affect Bangladesh since Cyclone Sidr in November 2007. A relatively strong tropical cyclone, it caused extensive damage in India and Bangladesh.

The storm was responsible for at least 4 deaths across Bangladesh and India; more than 1 million people were left homeless. Health officials in Bangladesh confirmed a deadly outbreak of diarrhea on 29 May, with more than 7,000 people being infected and four dying. In Bangladesh, an estimated 20 million people were at risk of post-disaster diseases due to Aila.

Meteorological history

Late on May 21, 2009, the Joint Typhoon Warning Center reported that a Tropical Disturbance had persisted about to the south of Kolkata, in India and had developed within the Southwest Monsoon. The disturbance at this time had a broad and poorly organized area of deep convection, which was located to the southeast of the low level circulation center which had consolidated into a single circulation during the previous 12 hours. Environmental analysis indicated that the system was in an area of favorable conditions to develop with low vertical wind shear and warm sea surface temperatures. During May 22, 2009, the disturbance developed further with a Tropical Cyclone a Cyclonic storm and had been named as Aila whilst located about to the southeast of Sagar Island. Aila became a severe cyclonic storm at 06UTC on May 25 and made landfall at its peak intensity (60kt, 967hPa) between 08 and 09UTC.

Preparations

Officials in India evacuated thousands of residents from coastal areas ahead of Cyclone Aila. In addition, several warning alerts were issued before the cyclone hit Kolkata; however, no alarm bells were rung.

In the Bhola District of Bangladesh, an estimated 500,000 people evacuated to higher areas and shelters as Aila neared landfall. Tourists were advised to stay in their hotels due to the short amount of time to prepare for the storm.

Impact

India

In India, at least 149 people were killed, two by electrocution, and hundreds others were left homeless as torrential rains led to flooding. High winds uprooted numerous trees, blocking roads throughout the region. More than 15,000 people in eight villages were reportedly isolated from relief crews by severe flooding. At least 18 of the 45 fatalities in West Bengal were in Kolkata, the region where Aila made landfall. All transit systems in the city of Kolkata were halted and daily life was at a standstill due to the storm. The areas and districts affected by the cyclone in West Bengal include East Midnapore, Howrah, Hooghly, Burdwan, South 24 Parganas and Kolkata.
In the West Bengal state, more than 100,000 people were left homeless as a result of Aila. At least 100 river embankments were breached by storm surge produced by the cyclone. Throughout the country, at least 150,000 people were left homeless. In northern areas of the state, heavy rains triggered numerous landslides in Darjeeling that killed 22 people and left 6 others missing. At least 500 homes were also damaged in the area. At least 50,000 hectares of agricultural land was lost during the storm, costing an estimated Rs. 125 crore (US$26.3 million). Throughout the state, an estimated 40,000 homes were destroyed and 132,000 others were damaged. At least 350,000 people affected by Aila. Later reports indicated that upwards of 2.3 million were displaced by the storm as 175,000 homes were destroyed and 270,000 were damaged.

The outer bands