Cyclone Aila 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.