Cyclonic Storm Viyaru, formerly known as Cyclonic Storm Mahasen, was an active tropical cyclone. It passed over the Bay of Bengal. It threatened Myanmar and Bangladesh. Its origin was a low pressure area in the Bay of Bengal. The low pressure area was created in the first week of May. Viyaru slowly developed. It became a depression on May 10 by almost remaining still. Gradually it gained speed on May 11 and became a cyclonic storm. It was the first storm of the season. At first the system's ultimate direction was not clear, but moved closer to eastern India. On May 14, the circulation of Viyaru turned northeastward.