 Cyclone Thane near peak intensity on December 29 | |
| Meteorological history | |
|---|---|
| Formed | December 25, 2011 |
| Dissipated | December 31, 2011 |
| Very severe cyclonic storm | |
| 3-minute sustained (IMD) | |
| Highest winds | 140 km/h (85 mph) |
| Lowest pressure | 969hPa (mbar); 28.61 inHg |
| Category 2-equivalent tropical cyclone | |
| 1-minute sustained (SSHWS/JTWC) | |
| Highest winds | 165 km/h (105 mph) |
| Lowest pressure | 956hPa (mbar); 28.23 inHg |
| Overall effects | |
| Fatalities | 48 |
| Damage | $235 million (2011USD) |
| Areas affected | Southern India, Sri Lanka |
IBTrACS /[1] | |
Part of the2011 North Indian Ocean cyclone season | |
Very Severe Cyclonic Storm Thane was the strongesttropical cyclone of 2011 within theBay of Bengal. Thane initially developed as a tropical disturbance within themonsoon trough to the west ofIndonesia. Over the next couple of days the disturbance gradually developed further while moving towards the northwest, and was declared a Depression during December 25, before being named Cyclonic StormThane the next day. Thane started to turn towards the west under the influence of asubtropical ridge ofhigh pressure before its development slowed during December 27, as a strong outflow and marginally favourablesea surface temperatures fought with persistentvertical wind shear. After its development had slowed during December 27, Thane became a Very Severe Cyclonic Storm during December 28, before as it approached the Indian states ofTamil Nadu, it weakened slightly. Thane then made landfall early on December 30, on the north Tamil Nadu coast betweenCuddalore andPuducherry and rapidly weakened into a depression.
Extratropical cyclone, remnant low, tropical disturbance, or monsoon depressionOn December 23, theJoint Typhoon Warning Center(JTWC) reported that a tropical disturbance had developed within themonsoon trough about 1540 km (960 mi) to the east ofMedan inIndonesia.[2][3] Convection surrounding the system had started to consolidate over a weak low level circulation centre, that was being fed by an enhanced westerly flow associated with the precursor system toTropical Cyclone Benilde.[2][3] Over the next couple of days the disturbance gradually developed further while moving towards the northwest, with aMadden–Julian oscillation increasing the systemboundary layers rotation.[3] The JTWC then issued aTropical Cyclone Formation Alert on the system during December 25 before designating as Tropical Cyclone 06B later that day as 1-minute wind speeds near the centre reached 65 km/h (40 mph) which is equivalent to a tropical storm.[4][5] TheIndia Meteorological Department(IMD) also reported during December 25 that the disturbance had organised sufficiently to be declared Depression BOB 05, while it was located about 1,000 km (620 mi) to the southeast ofChennai, India.[6]
Early on December 26, the IMD reported that the depression had intensified into aDeep Depression, before later that day reporting that it had intensified into acyclonic storm and named it Thane.[7][8] As it was named, Thane started to turn towards the west under the influence of a subtropical ridge of high pressure before its development slowed as strong outflow and marginally favourable sea surface temperatures fought with persistent easterly vertical wind shear.[9][10] Early on December 28, the JTWC reported that Thane had become equivalent to a category one hurricane on theSaffir–Simpson hurricane wind scale with 1-minute sustained windspeeds of 120 km/h (75 mph), while aneye feature had become visible on microwave imagery.[11] Later that day the IMD reported that Thane had become the firstVery Severe Cyclonic Storm of the season, with 3-minute sustained windspeeds of 120 km/h (75 mph).[12] During December 28, Thane continued to intensify, and developed a smallpinhole eye of about 20 km (10 mi), before the JTWC reported that Thane had peaked early on December 29 with 1-minute sustained wind speeds of 165 km/h (105 mph).[13][14] The IMD then followed suit and reported that the system had peaked as a Very Severe Cyclonic Storm with 3-minute sustained windspeeds of 140 km/h (85 mph).[15][16] During the rest of that day, the system continued to move westwards and weakened slightly as it started to interact with land.[17] Thane then made landfall as a borderline very severe cyclonic storm during December 30 on the north Tamil Nadu coast between Cuddalore and Puducherry. After it had made landfall, frictional forces made Thane rapidly weaken into a depression. As a result, the JTWC issued their final advisory during December 30, while the IMD continued to monitor the remnants of Thane until the depression weakened into a well-marked low-pressure area early on December 31.[18]
Forty eight people were killed by Cyclone Thane.[1] About 9 deaths were reported in Puducherry and 39 people were reported dead inCuddalore. Cuddalore and Puducherry were the worst affected by Thane. The storm made Cuddalore inaccessible by damaging road network and theNational Disaster Response Force and fire and rescue services had difficulty in reaching the cyclone affected fishing hamlets.[19]
Fishing activities had come to a complete halt in the cities ofChennai,Tiruvallur andKanchipuram in the wake of the storm after the warnings by the weather department were received. About 10,000 fishing boats were moved to safer locations in all fishing hamlets in these areas.Chennai Corporation kept its four permanent relief centers (Basin Bridge, Chintadripet, Gopalapuram andPerambur Barracks Road) ready to accommodate people in case of evacuation due to torrential rains. People from low-lying areas were shifted to community centers with adequate arrangements of food and medical round the clock.[20]
Tamil Nadu Chief MinisterJayalalithaa ordered the immediate release of₹ 150 crore towards relief and restoration of infrastructure damaged by the Cyclone Thane. She also directed the District Collectors, Deputy Collectors and department Secretaries to assess the extent of the damage caused by Cyclone Thane.[21]
700 fishermen were reported to be stranded near the Nizampatnam Bay area due to the rough sea conditions near the coast due to the cyclone. Owners had asked the government as well as the National Coast Guard for the fishermen's search and rescue after they could not communicate with them.[20]
The former chief minister of Andhra Pradesh,Nallari Kiran Kumar Reddy instructed all the district collectors of the concerned districts of the state, mainlyNellore andPrakasam districts to take all precautionary measures in anticipation of the approaching storm.APSRTC was asked to keep sufficient buses in reserve in case of evacuation of the people.[22] Officials reported that food stocks, drinking water, emergency power etc. were kept ready in reserves.[22]
