Cyclone Hazard and Response in Sri Lanka

 

 

Lareef Zubair

International Research Institute for Climate Prediction, Palisades, New York, U.S.A.,

Abstract

 

Sri Lanka has experienced four cyclones and 10 storms in the last century. After  two cyclones, in 1964 and 1978, there were calls for cyclone preparedness, adequate warnings, effective communication and effective response. In this paper, the seasonality and tracks of the storms and cyclones impacting Sri Lanka is described. The prospects for early warning and an effective response to cyclone warnings are also described. In the light of these calls,  the impacts of the cyclone of December 2000 is described.

 

Introduction

 

Sri Lanka has experienced four cyclones and 10 storms in the last century. After the last two cyclones, in 1964 and 1978, there were call for cyclone preparedness and effective response. This note is an attempt to characterize the cyclone hazard in Sri Lanka.  In this paper, the seasonality and tracks of the cyclones and storms impacting Sri Lanka is described. The prospects for early warning and an effective response to cyclone warnings are also described. In the light of these calls, the impact of the cyclone of December 27th, 2000 is described.

 

Cyclones in the Last Century

 

Cyclone that reached speeds above 120 km have passed through Sri Lanka in 18841, 19072, 19643,4 and 19785. In addition, there have been 10 storms of peak speeds between 60 to 120 kilometres that passed through Sri Lanka6-10 in the last century. Almost all of these storms and cyclones made landfall in the Eastern Province and carry on towards the North-West or the West.  There has been only one storm that reached Sri Lanka from the West2: in October 1967.   The cyclone prone districts are Ampara, Batticaloa, Trincomalee, Polonnaruwa, Vavuniya, Anurhadhapura, Mannar, Jaffna and Puttalam.

 

 

 

Date

Landfall

Exit to Sea

 

March 7, 1907

Batticaloa

South of Puttalam

December 22/23, 1964

Trincomalee

Mannar

November 23/24, 1978

 Between Kalkudah and Trincomalee 

Wilpattu

December 27, 2000

Trincomalee

Puttalam

 

Table1: Cyclones that passed through Sri Lanka in the last century based on Department of Meteorology records.

 

 

 

Figure 1: Historical Cyclone Tracks over Sri Lanka  and Cyclone Prone Areas in Sri Lanka

 

 

 

Seasonality of Cyclones

 

The cyclone season in the Bay of Bengal lasts from April to December11. Cyclones and Storms make landfall in Sri Lanka almost always only during the North-East monsoon period12-14. During this period, depressions that are formed directly East of Sri Lanka and spin off North-Westward are guided by the North-East winds towards the East Coast.  Sri Lanka is cyclone prone in November and December when the North-Eastern wind speeds are at its peak. 90% of the cyclonic storms reach Sri Lanka in these two months. The location of Sri Lanka is such that there is no similar mechanism for cyclones from the Arabian Sea to reach Sri Lanka during the South-West monsoon period. 

 

It has now become routine for forecasts of number of cyclones in a given season to be issued. Each year, the number of hurricanes making landfall the Eastern United States sea-board in the coming season is forecast several months in advance.  However such forecasts are not available for the Indian Ocean as yet.

 

                                                                                                         


 

Month

Number

Years

January

1

1906

February

Nil

 

March

1

1907

April to October

Nil

 

November

4

1922, 1966, 1978, 1992

December

8

1908, 1912, 1913, 1919, 1931, 1964, 1967, 2000

Total

14

 

 

Table
 2: Monthly frequency of cyclones and storms in Sri Lanka based on records from 1901 to 2000.  Source: Department of Meteorology, Sri Lanka.

 

 

 


Cyclone Warnings

 

The Department of Meteorology, Sri Lanka is in a position to issue storm forecasts in advance by a up to a few days. The Department has access to the NOAA, INSAT and METEOSAT satellite imagery. Warnings can be issued as soon as depressions form in the equatorial central Bay of Bengal. These satellite images are available in 6 hourly intervals and thus cyclone warnings are thus possible 2 days prior to landfall.

 

The lead-times for advance warnings and the precision of the forecasted tracks is crucial and one can improve on intuition by developing a computer model to track the path a depression may take and assess whether it will strengthen based upoun the wind, pressure, temperature and oceanic surface conditions15.

 

Satellite imagery has become available in the last two decades and is a considerable improvement on older techniques of cyclone forecasting.  Previously, empirical methods using wind and pressure measurements in Andaman Islands and in Sri Lanka and ship reports and radar were used for Cyclone Forecasting in the Bay of Bengal  by the Cyclone Warning Centre of the Indian Meteorological Department11.  In addition to the Indian Meteorological Department, the US Navy monitors cyclones and provides real time forecasts in the Indian Ocean. 

 

Response to Cyclone Warnings

 

While responsibility for cyclone forecasting is on the Department of Meteorology, it is not clear as to who really manages the response to hazard warnings. If there is to be any improvement in response to cyclones in the future, the responses to the present cyclones must be evaluated.

 

All over the world, there are communication difficulties due to the scientific background of meteorologists and the humanities background of the disaster managers and the media. The usual modus of press releases, queries and corrections will not do.  There is a need for timeliness and appropriate alerting with which hazard forecasts are communicated among forecasters, government officials, mass media and the public. Emergency managers cannot go through the usual Administrative and Financial Rules.  Clear demarcation of responsibilities and adequate authority for the responsible officials is essential for an effective response.

 

Cyclone Preparedness

 

Even without cyclone warnings, many steps can be taken in the cyclone prone areas to mitigate risks. These include guidelines on infrastructure planning, Cyclone-resistant buildings, land management and coastal protection. Vegetation in the North-Eastern sea board of Sri Lanka must be protected along with natural barriers that withstand the storm surge. Regions of the coasts where the tides will surge into land such as Kalkudah must be identified. Unfortunately at present, coastal conservation efforts are focussed on the South-Western coast rather than the vulnerable North-Eastern coast due to the war.  In addition, irrigation managers may take steps such as drawing down desiliting and removing obstructions before October. Fisherman could be encouraged to take steps to protect boats in November and December.   

 

The 1978 Cyclone

 

The damages from the 1978 cyclone included 915 deaths, one million affected and a storm surge of up to 2 kilometres in the Eastern province.  In response to this cyclone, there were several programs that looked into cyclone preparation. Among these were

a)      A program funded by the UNDP was carried out under the auspices of the Ministry of Local Government, Housing and Construction10,

b)      A workshop conducted by the Sri Lanka Foundation Institute and a report presented by the Committee on “Design, Construction and Regulations for Buildings in the Cyclone prone areas of Sri Lanka10,

c)      A report of the technical assistance program from the Australian governments and proposals for foreign aid for supplying instrumentation for recording cyclones in the east coast. Precise wind measurements are of particular importance not only from a meteorological standpoint but also in terms of evaluating proper design of buildings and other infrastructure10.

d)      The Arthur C. Clarke Centre conducted a Workshop on Disaster Warnings.

e)      Asian Disaster Preparedness Centre in Bangkok has made various proposals.

 

In addition, there were several theses and research papers on the 1978 cyclone and its impacts. Thus there is no shortage of studies or proposals.  Among the proposals from these workshops10 and studies that are documented are an

 

For example, were those responsible for the restoration of the Jethavanaramaya Dagoba aware of the cyclone hazard and did they take the appropriate steps to safeguard the structure during construction. 

 

The 2000 Cyclone

 

The cyclone that passed over Sri Lanka and Tamil Nadu on the 26th and 27th of December left a trail of destruction in the Eastern, North-Central and North-Western Provinces of Sri Lanka. It made landfall in Trincomalee and decelerated as it cut across Polonnaruwa, Anurhadaphura and Puttalam Districts.  Some of the initial reports of damage were:

 

·        8 persons dead

·        55,000 families displaced

·        50 fishing boats washed to sea

·        acres of rice, banana, coconut washed away

·        water, electricity and telecommunications in the Trincomalee, Anurahadhapura, Puttalam, Vavuniya districts were disrupted

·        Rivers including Kala Oya and Reservoirs including Parakrama Samudraya spilled over

·        Part of Jethavanaramaya dagoba (Buddhist monument from the 6th century only exceeded in height by the Pyramids of Egypt in the Ancient world) washed away

 

The impacts of the 2000 cyclone were compounded by anomalously high rainfall in November and pre-existing wet ground conditions. Thus the dangers from a cyclone were accentuated. 

 

Summary

 

Cyclone warning may be issued more than 24 hours in advance at present.  With such forecasts and an educated anticipation of the seasonality of cyclones fatalities may be avoided and much of the damage may be mitigated. Cyclone response can be improved by conducting research on forecasting cyclone tracks, enhanced likelihood of cyclones during different seasons, the compounding of the impact of cyclones from the weather in the preceding months and enhanced measurements of wind in the East. In addition to cyclone forecasts, timely and widespread communication and adequate response management is needed. Some of the damage from cyclones may be mitigated from cyclone preparedness in infrastructure, coastal protection and maintaining adequate vegetation and suitable river management. In addition, there are pitfalls in the communication of hazards among scientists, state officials, the mass media and the public, which can obscure even the best forecasts. In addition, effective response can flow only from clear responsibility, adequate authority and a planned response strategy.

 

 

 

References

 

1. Nevill, H., Submersion of Lanka and cyclone wave, 1884. Taprobanian. (a Dravidian journal of Oriental Studies in and around Ceylon; edited by Hugh Nevill (Bombay) ), 1888, 3(4):74.

 

2. Lewis, J.P., The Kutiraimalai tradition and some cyclones. Ceylon Antiquary and Literary Register, 1924, 9(3):170-171.

 

3. Ekanayake, L.A.D.I., Cyclone over Ceylon, December 1964,  Weather, 1968, 23(5).195-197.

 

4. Ekanayake, L.A.D.I., The Trincomalee-Mannar cyclone of 22/23 December 1964

Proceedings of the 21st Annual Session, Ceylon Association for the Advancement of Science 1965, 21(1).52-53p.

 

5. Suppiah, R., Some aspects of the cyclone over Sri Lanka, November 23/24, 1978

Institute of Geosciences, University of Tsukuba, Japan, Climatological Notes, 1982, 30.125-139.

 

6. Jameson, H., Whirlwind at Veyangoda, Ceylon, 20th July 1921, Quarterly Journal of Royal Meteorological Society, 1922, Lxviii.59-60p.

 

7. Ekanayake, L.A.D.I., The Jaffna cyclone of 1955, Proceeding of the 12nd Annual Session, Sri Lanka Association for the Advancement of Science 1956, 12.41-42p.

 

8. Ekanayake, L.A.D.I., The Chilaw cyclone of 1967 October, Proceedings of the 24th Annual Session, Ceylon Association for the Advancement of Science 1968, 24(1).56-57p.

 

9. Ekanayake, L.A.D.I., Mullaitivu-Mannar cyclone of 9th November 1966, Proceedings of the 23rd Annual Session, Ceylon Association for the Advancement of Science 1967, 23(1).56-57p.

 

10. Sri Lanka Foundation Institute, Sri Lanka, Construction and Preparation in Cyclone Prone Areas of Sri Lanka; Sri Lanka Foundation Institute Seminar - Rep. No. 20, 1980, Colombo.

 

11. Pant, G.B. and Rupa Kumar, K., Climates of South Asia, Wiley, Chichester, 1995.   

 

12. Bamford, A.J., Cyclonic movements in Ceylon, Ceylon Journal of Science Section E., 1926 1(1).15-37p.

 

13. Thambyahpillay, G.G.R.Tropical cyclones and the climate of Ceylon, University of Ceylon Review, 1959, 17(3/4).137-180p.

 

14. Jayamaha, G.S., Tropical cyclones, Journal of Sri Lanka Meteorological Society, 1973, 2(1) 27-29.

 

15. Abhayasingha Bandara, K.R., Forecasting of Cyclone Tracks with particular reference to the Indian Ocean, M.Sc. Thesis, University of Reading, U.K., 1983.

 

16. Priyasekara, D.G., Batticaloa Cyclone, 1978 November 23rd, M.Sc. Thesis, University of Peradeniya, , 21p.

 

2. Department of Social Services, Statistics on Disaster Events in Sri Lanka, Colombo, 1995.

6. Sri Lanka Foundation Institute, Sri Lanka, Construction and Preparation in Cyclone Prone Areas of Sri Lanka; Sri Lanka Foundation Institute Seminar - Rep. No. 20, 1980, Colombo.

 

7. United Nations Disaster Relief Coordinator on the cyclone in Sri Lanka 23/24 November, UNDRO Case report, 1979, (6):28p.

 

 

9. De Silva M.B.G., Cyclones, Proceedings of Disaster Warning Workshop, Arthur C. Clarke Centre for Modern Technology, Moratuwa, 1996.

 

10. De Silva, C.H., Natural Events of National Concern, Sri Lanka, Country Report, NBRO, Colombo. 

 

12. United Nations Disaster Relief Coordinator on the cyclone in Sri Lanka 23/24 November, UNDRO Case report, 1979, (6).28p.

 

 

 

 

Table:

1.      Cyclone impacting Sri Lanka in the last century

2.      Cyclonic Storms impacting Sri Lanka in the last century