Cyclone Aila

Severe Cyclonic Storm Aila

Severe cyclonic storm (IMD scale)
Category 1 (Saffir–Simpson scale)
Severe Cyclonic Storm Aila at peak intensity
Formed	May 27, 2009
Dissipated	May 26, 2009
Highest winds	3-minute sustained: 110 km/h (70 mph) 1-minute sustained: 120 km/h (75 mph)
Lowest pressure	968 hPa (mbar); 28.59 inHg
Fatalities	339 total
Damage	$295.6 million (2009 USD)
Areas affected	India, Bangladesh
Part of the 2009 North Indian Ocean cyclone season

Severe Cyclonic Storm Aila was the worst natural disaster to affect Bangladesh since Cyclone Sidr in November 2007. The second tropical cyclone of the 2009 North Indian Ocean cyclone season, Aila formed over the Bay of Bengal on May 23. A relatively strong tropical cyclone, it caused extensive damage in India and Bangladesh.

The storm was responsible for at least 339 deaths across Bangladesh and India; more than 1 million people were left homeless. Health officials in Bangladesh confirmed a deadly outbreak of diarrhoea 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.

Late on May 21, 2009, the Joint Typhoon Warning Center reported that a Tropical Disturbance had persisted about 950 kilometres (590 mi) 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 temperaures. During May 22, 2009, the disturbance developed further with a Tropical Cyclone Formation Alert being issued early the next day by the JTWC as the low level circulation center had become stronger and more defined. Later that morning RSMC New Delhi designated the disturbance as Depression BOB 02.

During the day Depression BOB02 continued to slowly intensify until early the next day when it was upgraded to a Deep Depression by RSMC New Delhi, and designated as Tropical Cyclone 02B by the JTWC. This came as satellite imagery had shown further organization of the depression. Later that day, RSMC New Delhi reported that the deep depression had intensified into a Cyclonic storm and had been named as Aila whilst located about 350 kilometres (220 mi) 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.