Cyclonic winds, cyclones: South Asia
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In brief
See graphic
The India Meteorological Department (IMD) classifies cyclonic winds into three categories--cyclonic disturbance (maximum wind speed 59kmhr), cyclones (wind speed 60 to 90 kmhr) and severe cyclones (wind speed 90 kmhr or more). Cyclone data for the years 1891 to 2012 shows a seasonal pattern. The mildest of these turbulent wind systems -cyclonic disturbances -peak in the monsoon season with an average of six to seven such incidents a year. The probability of cyclones and severe cyclones, on the other hand, is highest in the post-monsoon months. The data also shows that on an average, the Bay of Bengal is hit by at least one severe cyclone and a minimum of two cyclones each year
Naming tropical cyclones
The Hindustan Times, December 9, 2016
In 2016, Bay of Bengal witnessed Roanu, Kyant, Nada and Vardah (names of the tropical cyclones) which also affected India.
Vardah is the Arabic and Urdu word for ‘rose’, a name provided by Pakistan in the comprehensive nomenclature list for cyclones in the Arabian sea and Bay of Bengal.
In September 2004, an international panel on tropical cyclones decided that countries from the region would each put in names, which would be assigned to storms in the Bay of Bengal and Arabian Sea.
Eight countries -- India, Pakistan, Bangladesh, Maldives, Myanmar, Oman, Sri Lanka and Thailand – participated and came up with a list of 64 names.
In the event of a storm, the Regional Specialized Meteorological Centre, New Delhi, selects a name from the list. The late origin of this naming system -- unlike storms in the Atlantic, which have been getting named since 1953 -- was ostensibly to protect sensitivities in the ethnically diverse region.
The purpose of the move was also to make it easier for “people easily to understand and remember the tropical cyclone/hurricane in a region, thus to facilitate disaster risk awareness, preparedness, management and reduction,” according to the IMD.
Citizens can submit names to the Director General of Meteorology, IMD, for consideration, but the weather agency has strict rules for the selection process.
A name, for instance, ‘should be short and readily understood when broadcast’. The names must also be neutral, ‘not culturally sensitive and not convey some unintended and potentially inflammatory meaning’.
Furthermore, on the account of the ‘death and destruction’ a storm in the Indian Ocean causes, their names are retired after use, unlike those in the Atlantic and Eastern Pacific lists, which are reused every few years.
Cyclone Vardah: December 2016
Andaman and Nicobar Islands
Please see: Andaman And Nicobar Islands: Natural calamities
Tamil Nadu
The Hindu, December 12, 2016
Cyclone Vardah heads towards Chennai shores
Cyclonic storm Vardah is likely to make landfall by December 12, 2016 along north Tamil Nadu and south Andhra Pradesh coast, close to Chennai, accompanied by strong winds with speeds of 80 to 90 kmph.
S. Balachandran, director, Area Cyclone Warning Centre in Chennai, told the media on Sunday the rains would gradually increase from the morning of December 12 and were expected to last until the next day in the northern districts of Chennai, Tiruvallur and Kancheepuram.
Moderate rain
S.B.Thampi, Deputy Director General of Meteorology said, most places along north Tamil Nadu and south Andhra Pradesh coasts would get to light to moderate rain with possibilities of heavy rainfall of up to 20 cm as the system makes landfall.
“During landfall, Chennai, Tiruvallur, Kancheepuram and Puducherry will get rainfall and once the system crosses, Vellore and Dharmapuri will begin to get rains,” he said.
Chief Minister O. Panneerselvam chaired a meeting in the Secretariat on Sunday to review the preparations by government agencies. Schools and colleges in Kancheepuram, Tiruvallur, Villupuram and Cuddalore districts have been closed on Monday.
The government also issued an advisory to private undertakings and establishments to permit their staff to avail of a holiday or to work from home.
“Due to the storm surge, the seas are expected to be rough and the tidal wave will be 1 m higher than normal. Fishermen have been warned not to venture out into the sea,” he said.
National Disaster Response Force (NDRF) and State Disaster Response Force teams have been stationed at Chennai, Tiruvallur and Kancheepuram districts as a precautionary measure.
Impact
The Hindu, December 13, 2016
Cyclone Vardah made landfall in Chennai on December 12, 2016 between 3 p.m. and 5 p.m., uprooting trees, defacing highrises, smashing cars, disrupting public transport and telecommunication, bringing the metropolitan area to a standstill.
The weather system that was first noticed nearly five days ago, grew into a ‘very severe cyclonic storm’ and by the time it crossed the city near the Chennai Port, it had weakened into a ‘severe cyclonic storm’ with maximum wind speeds touching 110 kmph-120 kmph.
Lull as eye crosses city
This was a large weather system, measuring nearly 40 km in diameter, which explains the time taken for the system to cross.
There was a lull between 2-30 p.m. and 5 p.m. as the eyewall of the cyclone was in transit and it normally is empty, bringing very little, or no rainfall.
The windspeeds decreased to 60-70 kmph, and the system now a ‘cyclonic storm’ moved westwards, bringing moderate to heavy rainfall to the interior areas as well. Rainfall over the northern coastal districts is expected to continue till Tuesday noon. Vardah, an Urdu word meaning red rose, contributed by Pakistan, will turn into a deep depression early on Tuesday, sources said.
While vast devastation was caused to trees and property, the total rainfall received has only partly bridged the city’s rain deficit. Before Vardah struck, the annual rainfall deficit was over 60 cm, and while the storm has narrowed the gap, there is a solid 40 cm of rainfall the city needs for the reservoirs to fill up and meet its water needs until the next monsoon.
Water managers expect another spell of rainfall before the next monsoon.
Official sources said three people had died from rain-related causes in the State on Monday. Chief Minister O. Panneerselvam announced a solatium of Rs. 4 lakh each to the families of the victims.
Corporation officials pegged the number of trees fallen at 568 along the 471 bus routes and over 33,000 interior roads in the 426 sq km of the Greater Chennai Corporation limits, impeding the flow of traffic.
Most of the suburbs were cut off from other parts of the metropolitan area.
As dark clouds gathered over the city all day, power supply was disrupted. Banking transactions were affected and PoS devices failed at retail outlets.
Holiday for schools
The Tamil Nadu government declared Tuesday would be a holiday for educational institutions in three districts.
“All government, government-aided, private schools, colleges and other educational institutions in Chennai, Kancheepuram and Tiruvallur districts will remain closed on December 13,” an official release said.
Steps by the central government
The Hindu, December 19, 2016
Central team to visit TN to assess Vardah impact
At least 18 people were killed when cyclone Vardah hit Tamil Nadu and Andhra Pradesh on December 12.
The team, headed by Joint Secretary Praveen Vashishtha from the Home Ministry comprised officials from the Ministries of Finance, Agriculture, Industries and Rural Development, among others.
Immediately after the cyclone, the Chief Minister had sought disbursal of Rs. 1,000 crore as an interim relief package. However, the Central Government had responded by releasing an interim aid of Rs. 500 crore, which the State felt was inadequate.
Mr. Panneerselvam, accompanied by officials, called on Tamil Nadu Governor (in-charge) Ch. Vidyasagar Rao at the Raj Bhavan. The meeting, described as a courtesy call in an official release, came as a surprise since it came just one day ahead of the Chief Minister’s Delhi visit.
Andhra Pradesh
The Andhra Pradesh government remains on high alert, monitoring the progress of cyclone Vardah with real-time updates from the Indian Space Research Organisation (ISRO), even as the system changed course towards the northern Tamil Nadu coast. Its initial track forecast landfall between East Godavari (Kakinada) and Nellore districts.
The government has been tapping into ISRO’s data following an understanding reached with the agency earlier this year for weather forecasting.
Naidu meets ISRO team
Chief Minister N. Chandrababu Naidu, who cancelled his Dubai visit to monitor the likely impact of Vardah, held a meeting with ISRO scientists on Saturday.
According to official sources, the State government is getting inputs from the ISRO through its National Remote Sensing Centre and other wings round the clock.
Contingency plan
Later in a teleconference, Mr. Naidu told officials of various departments that the cyclone could cross the coast between Sriharikota and Chennai by Monday evening and trigger heavy rains in Chittoor, Kadapa and Nellore districts. He called upon the heads of departments to be prepared to face the contingency by drawing on their experience during Cyclone Hudhud two years ago.
NDRF teams have been deployed in Sullurpet and Tada in Nellore district. Four IAS officers — Mukesh Kumar Meena, B. Sridhar, M. Ravi Chandra and Ram Gopal — have been deputed as special officers to Prakasam, Nellore, Chittoor and Kadapa to handle the situation.
Cyclone Mora: May 2017
Bangladesh and northeastern India
Cyclone Mora that lashed Bangladesh's coastlines forcing the evacuation of millions of people and shutting the country's main port and river transport, killed at least six people in Cox’s Bazar and Rangamati before moving to northeastern India.
The cyclone, which lashed the coastal belt with a wind speed of 128 kmph and made landfall at around 6 a.m. (0000 GMT), cut off Kutubdia, Moheshkhali and Teknaf from other parts of the country.
Road transportation was affected, phone lines were disrupted, more than 20,000 houses destroyed and hundreds of trees were uprooted. The Disaster Management Ministry said it moved to safety more than 2.5 million people in 10 coastal districts which were most vulnerable to the tropical storm as the Met Office upgraded the cyclone warning to Great Danger No. 10, the highest level.
About 18 million people live in 19 coastal districts, 10 of them in high-risk areas. As it moved towards India, heavy showers and gusty winds lashed Mizoram on Tuesday disrupting power and telecommunication network, damaging houses and triggering landslides.
Cyclone Ockhi: December 2017
In brief
The name Ockhi was given by Bangladesh, (In Bengali, ockhi means ‘eye’.)
Cyclones are no strangers to the Indian coast, our east coast in particular witnessing several cyclonic storms each year. Yet, Ockhi, the latest powerful cyclone, is unlike other recent ones.
What is special about Ockhi?
Mostly, the area in which it developed. Cyclones are known to originate in both the Bay of Bengal and the Arabian Sea sides of the northern Indian Ocean; there is much more frequency on the Bay of Bengal side though, especially of the stronger cyclones — in fact, the Bay of Bengal side witnesses four times more cyclones than the Arabian Sea side on average.
But Ockhi originated near the south-western coast of Sri Lanka, and travelled very near the southern-most tip of the Indian mainland, along the coasts of Tamil Nadu and Kerala, towards the Lakshadweep islands, where it was at its most powerful. It weakened considerably after that and continued further, taking a north-easterly turn towards the Maharashtra and Gujarat coastlines —cyclones in this area are not a common phenomenon.
Why does the Bay of Bengal have more cyclones than the Arabian Sea?
Meteorologists say the relatively colder waters of the Arabian Sea are not conducive to the formation and intensification of cyclones. Additionally, the eastern coast of India receives cyclones that form not just in the Bay of Bengal, mostly around the Andaman Sea near the Andaman and Nicobar Islands, but also those travelling from the Pacific Ocean, where the frequency of ‘typhoons’, as these are called there, is quite high. Most of these cyclones weaken considerably after encountering a big landmass. Therefore, these do not travel to the Arabian Sea side. The western coast of India thus witnesses only those cyclones that originate locally or the ones, like Ockhi, that travel from the Indian Ocean near Sri Lanka.
How powerful was Ockhi?
Ockhi was described as a ‘very severe cyclonic storm’, the third strongest category according to the definitions used by the India Meteorological Department (IMD). Cyclones are categorised by the maximum wind speed they generate. At its most powerful, Ockhi had wind speeds between 155 and 165 km per hour, touching the upper border for ‘very severe cyclonic storm’.
Cyclones with wind speeds between 165 and 220 km per hour are classified as ‘extremely severe cyclonic storm’. Those with even higher wind speeds are called ‘super-cyclones’. The most famous instance of a ‘super-cyclone’ was the one that hit the coast of Odisha in October 1999. It was the strongest-ever cyclone recorded in that area, with wind speeds touching 260 km per hour. It was also the most devastating cyclone to have hit India.
The 2013 Phailin cyclone very nearly got categorised as a super-cyclone. It had maximum wind speeds of around 220 km per hour.
Cyclone forecasts by the IMD in the recent past have been made five to six days in advance, thereby minimising the damage caused — was the IMD late in issuing a warning for Ockhi?
How early the forecast is depends on how far we are from the place where the cyclone is emerging. Many of the big cyclones in recent years, like Phailin in 2013, Hudhud in 2014 or Vardah in 2016, developed near the Andaman Sea. From there, it took those cyclones about five to six days to hit the Andhra Pradesh or Odisha coasts.
These forecasts can be made only after an emerging depression is detected to have the properties of a cyclonic storm. This was true in the case of Ockhi as well. But the origin of Ockhi was much closer home. The cyclone formation was detected during the morning of Wednesday, November 29. An alert was issued around noon. But many areas in Tamil Nadu and on the Kerala coast started feeling the impact from Thursday itself. A day later, the Lakshadweep islands bore the brunt of the cyclone. Because it developed nearby, the lead time for the forecast was much less than in other recent cyclone cases.
Impact, state-wise
Goa
Prakash Kamat, December 5, 2017: The Times of India
Ripple effects
High tides due to the ripple effectasof Ockhi cyclone that hit Tamil Nadu, Kerala and Lakshadweep damaged several beach shacks, temporary eateries and other tourist structures along Arambol, Morjim, Mandrem and Cavelossim.
Several shacks have reportedly been affected by the swelling of waters along the coastline, due to the twin impact of Ochki cyclone and the super moon last night. Several videos of sea water creeping dangerously close to beach shacks and shack workers scurrying to salvage their beach beds and other equipment were also uploaded to social media on Monday, triggering panic among the tourism and travel industry stakeholders, even as government sources said that efforts were on to declare the damage as a state disaster. The maximum losses was reported in the coastal sub-district of Pernem, where nearly 30 shacks were damaged.
Over 10 shacks at Morjim were damaged while eight each in Mandrem and Arambol too were damaged due to the high waves.
Shack owners claimed that mattresses, plastic tables and other property were damaged by the waves lashed the shacks. There were reports of damages to electronic items such as refrigerators. The water level was so high that the waves inundated their kitchens and destroyed food items which were kept on ground.
Mr. D’Souza said this may force the government to reconsider the location of temporary shack when permits are allotted.
“It is, nevertheless, an eye opener not only for Goa, but other coastal states too, to review tourism trade activities close to the shoreline,” he added.
Meanwhile, a government spokesperson said on Sunday that fishermen have been asked to not venture into the sea at least for the next three days.
A report from North Goa Magistrate Nila Mohanan said that there was considerable damage to almost 50 shacks in Morjim, Mandrem, Arambol and Querim beaches in Pernem taluk of North Goa. In Bardez taluk, only soil erosion in Anjuna and Baga beaches and damage to a retaining wall at Coco beach in Nerul have been been reported.
