Cyclone Viyaru

**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.

Myanmar recommended a large evacuation in order to be prepared for the storm; however, for this reason people wanted to escape by boat. As a result, they made boats overcrowded, and one or more boats capsized. This killed at least eight people. The storm had extensive cloud mass, which brought unsettled weather to Sri Lanka, Thailand, and southeastern India. Severe storms in India and Sri Lanka killed 15 people and caused major damage. One person was killed in Thailand.

The name _Mahasen_ caused some argument from nationalists and officials in Sri Lanka. They claimed that the name Mahasen comes from a Sinhala king. He brought prosperity to the island. So naming a destructive force of nature after him would be improper. Sri Lankan authorities instead have not given the storm a name.

Cyclone Viyaru struck Southern Bangladesh on 16 May 2013. The speed of the wind was about 100 km/h.

## Weather history

An area of convection first appeared on May 4. It slowly moved eastwards and organized into a low pressure area on May 8. A pulse in the Madden–Julian oscillation, together with a convective Kelvin wave allowed the system to develop. These oscillations also caused Tropical Storm Jamala to form. The JTWC later issued a Tropical Cyclone Formation Alert (TCFA) on May 10, after the system became more organized. The IMD upgraded it to a well-marked low pressure area. Later the same day, JTWC issued the first warning for the storm. JTWC designed it 01B, followed by the IMD upgrading the storm into a depression, and later into a deep depression.

### Recent storm information

As of 0830 IST (0300 UTC), 16 May 2013, Cyclonic Storm Mahasen was located near latitude 21°N and longitude 90°E, about  south-southeast of Kolkata and  southwest of Chittagong. The storm is forecast to maintain power. It is moving northeastwards. It is expected to cross the Bangladesh coast close to Chittagong by evening of 16 May. Sustained maximum surface wind speed is estimated at , gusting to . Estimated minimum central pressure is at 988 mbar. Dvorak intensity of the storm is at T2.5.

## Other websites

- India Meteorological Department
- Joint Typhoon Warning Center
- Corporate Disaster Resource Network, India

- For the latest information:
- The IMD's Cyclone warning for Indian coast.
- The IMD's Tropical Cyclone Advisory and forecast track .
- The JTWC's Tropical Cyclone warning and forecast track.

## Infobox (hurricane)

- **name**: Cyclonic Storm Viyaru
- **type**: Tropical storm
- **year**: 2013
- **basin**: NIO
- **image location**: Mahasen May 13 2013 0755Z.jpg
- **image name**: Cyclonic Storm Viyaru over the Bay of Bengal on May 13
- **formed**: May 10, 2013
- **dissipated**: May 17, 2013
- **3-min winds**: 45
- **1-min winds**: 50
- **pressure**: 990
- **areas**: Sri Lanka, Southeastern India, Thailand, Myanmar, Bangladesh
- **fatalities**: At least 24 total
- **hurricane season**: 2013 North Indian Ocean cyclone season