correspondence Cyclone Nargis storm surge in Myanmar To the Editor — Tropical cyclone of 100,000 striking India and Bangladesh tropical cyclone track included in the Nargis (category 4 on the Saffir–Simpson (Supplementary Fig. 1). Damage estimates International Best Track Record for Climate Hurricane Scale, SSHS) made landfall on at over $10 billion made Nargis the most Stewardship database2 has made a direct 2 May 2008, causing the worst natural destructive cyclone ever recorded in the landfall in Myanmar’s Ayeyarwady river disaster in Myanmar’s recorded history. Indian Ocean. Here we analyse the cause of delta at an untypically low latitude near Official death toll estimates exceed 138,000 the humanitarian disaster based on physical 16° N. In 2006, a similar tropical cyclone fatalities1 making it the eighth deadliest and societal observations. (Mala, category 4, SSHS) made landfall in cyclone ever recorded worldwide. Since On 28 April 2008, Nargis was located Myanmar at 17.6° N causing only 22 deaths the 1970 Bhola cyclone, which caused up near the centre of the Bay of Bengal and after a well executed evacuation effort, and to 500,000 fatalities, Nargis represents the upgraded to a category 1 cyclone (SSHS). the 2004 Indian Ocean tsunami, which deadliest tropical cyclone worldwide and The tropical cyclone developed sustained affected Myanmar’s Andaman coast, resulted one of the worst natural disasters, with winds over 210 km h–1, with gusts up to in only 71 fatalities. the exceptions of the 2004 Indian Ocean 260 km h–1, before landfall in Myanmar Three months after cyclone Nargis, access tsunami and the 1976 Tangshan earthquake. on 2 May as a category 4 storm (SSHS). It was granted to the hardest-hit Ayeyarwady The Bay of Bengal has generated seven reached Yangon approximately 12 h later delta for the 9–23 August 2008 storm-surge tropical cyclones with death tolls in excess as a category 1 storm (SSHS). No previous reconnaissance, which surveyed coastal and inland villages encompassing the a Bogale and Ayeyarwady rivers. The boat 17° N and helicopter survey spanned 150 km 3 May 1 parallel to the cyclone track between Pyapon 0 50 km 0:00 UTC and Pyinkhayan, encompassing the 20 Yangon hardest-hit settlements such as Pyinsalu. High-water marks, overland flow depths 30' 2 May 18:00 UTC and inundation distances were recorded Bogale Pyapon based on established protocol3 (Fig. 1). 2 Survey point Labutta The Nargis high-water marks surpassed 2 May Cat. 1 119-153 km h–1 the 2004 Indian Ocean tsunami run-up at - 12:00 UTC y –1 4 ar 16° N 3 d Cat. 2 154-177 km h corresponding locations and the storm a ey 4 yan w –1 surge peaked at over 5 m in the landfall Pyinkha Ay Cat. 3 178-209 km h auk Ka Latt area. In most areas, roughly 2-m-high 2 May Ky Pyinsalu Aya Cat. 4 210-249 km h–1 6:00 UTC Aung Hlaing storm waves were superimposed on surge 30' 94° E 30' 95° E 30' 96° E30' 97° E levels. Inundation distances reached 50 km inland from the nearest coastline, based on flooding direction. The Nargis high- b 7 water measurements are comparable to 6 Surge elevation observations in Louisiana’s Mississippi delta 5 Ground elevation after Hurricane Katrina5. Both Nargis and 4 Wave elevation Katrina affected major river deltas as both Vertical erosion ation (m) 3 tracks crossed river mouths. v 2 Tsunami height Ele Ephemeral coastal erosion, and 1 Tsunami height vegetation and infrastructure damage were 0 (ref. 4) documented. More than 1 m of vertical –1 erosion and 100 m of land loss were –2 c measured at various coastal locations from 100 the landfall area to the Ayeyarwady river e (%) 80 Fatality rate mouth (Supplementary Fig. 2). Drinking 60 water wells were flooded with saltwater, entag Residential 40 destruction rate scoured and left stranded in the surf zone. Perc 20 A golden Buddhist stupa, originally built 0 on dry land, pierced the water surface 150 m offshore from Aya. Deforestation Figure 1 | Field observations of the cyclone Nargis storm surge in Myanmar, which made landfall on for charcoal and rice paddies as primary 2 May 2008. a, NASA MODIS Rapid Response imagery with a UNOSAT flood overlay (in red) modified land-use had left few primary growth based on ground reconnaissance; storm track and categories are shown in yellow. b, Measured storm- mangroves, which may have provided some surge and storm-wave heights for the region between 94 and 96° E, compared with the 2004 Indian wave attenuation6 within 30 km of the coast Ocean tsunami heights (see Supplementary Table 1). c, Recorded mortality and residential destruction (Supplementary Fig. 3). rates in the region between 94 and 96° E (see Supplementary Table 2). Measurement accuracies: ±0.1 m Catastrophic peak fatality rates exceeded for vertical measurements and ±0.3 m for wave-height estimates. 80% in the hardest-hit villages. The fatality 448 NATURE GEOSCIENCE | VOL 2 | JULY 2009 | www.nature.com/naturegeoscience © 2009 Macmillan Publishers Limited. All rights reserved ngeo_558_JUL09.indd 448 18/6/09 12:29:45 correspondence rates in the initial landfall area were numerical model validation, which is widely 6. Barbier, E. B. et al. Science 319, 321–323 (2008). surprisingly low because of spontaneous absent for historical events in the Bay of 7. Sieh, K. Phil. Trans. R. Soc. A 364, 1947–1963 (2006). 8. Synolakis C. E. & Bernard, E. N. Phil. Trans. R.. Soc. A self-evacuation facilitated by nearby high Bengal. The inundation penetrated 50 km 364, 2231–2265 (2006). ground. All interviewed eyewitnesses inland inhibiting last-minute evacuations ignored warnings owing to lack of cyclone owing to the lack of high ground at most Acknowledgements awareness and evacuation plans, absence of locations. Unfortunately, the widely This research was in part supported by the Department high ground or shelters, and no indigenous deforested, low-lying and densely populated of International Development’s Pyoe Pin Programme, knowledge of comparable previous storm- Ayeyarwady delta with its poor housing UK. The disaster zone access was made possible by surge flooding in the Ayeyarwady river construction remains extremely vulnerable P. Win (Mingalar Myanmar), Y. M. Htoon (Myanmar Development Foundation), J. Broadhead (United Nations delta. Residents surprised by the deadly to future storm-surge flooding, potential Food and Agricultural Organization), A. M. Kyu (National flooding struggled with capsizing small sea-level rise or tsunami. Coastal protection Committee for Environmental Affairs) and U. Soe Kyi boats and canoes, while some ‘floaters’ in the Bay of Bengal must be approached (Ministry of Social Welfare, Relief and Resettlement). We survived by tying themselves to a tree. In with community-based education and also acknowledge the World Food Program for providing a sharp contrast, the residents of the Gwa awareness programs suited for a multi- helicopter exit flight. coastline, frequently struck by cyclones hazard perspective7,8. ❐ such as Mala, are aware of cyclone Hermann M. Fritz1*, Christopher D. Blount1, hazards and have evacuation plans. Gwa References Swe Thwin2,3, Moe Kyaw Thu3 and Nyein Chan3 is located 150 km north of the Nargis 1. http://www.emdat.be 1Civil and Environmental Engineering, Georgia landfall area and has high ground nearby 2. Knapp, K. R., Kruk, M. C., Levinson, D. H. & Gibney, E. J. Eos Institute of Technology, Savannah, Georgia 31407, facilitating evacuation. 90, 46 (2009). USA, 2Myanmar Coastal Conservation Society, 3. Fritz, H. M. et al. Estuar. Coast. Shelf Sci. 74, 12–20 (2007). Yangon, Union of Myanmar, 3Mingalar Myanmar The field survey in the aftermath of 4. Satake, K. et al. Earth Planets Space 58, 243–252 (2006). cyclone Nargis provides ephemeral storm- 5. Fritz, H. M. et al. J. Geotech. Geoenv. Eng. NGO, Yangon, Union of Myanmar. surge data that is critically important for 34, 644–656 (2008). *e-mail: [email protected] NATURE GEOSCIENCE | VOL 2 | JULY 2009 | www.nature.com/naturegeoscience 449 © 2009 Macmillan Publishers Limited. All rights reserved ngeo_558_JUL09.indd 449 18/6/09 12:29:45 SUPPLEMENTARY INFORMATION DOI: 10.1038/NGEO558 Supplementary Information to accompany Cyclone Nargis storm surge in Myanmar Hermann M. Fritz, Christopher D. Blount, Swe Thwin, Moe Kyaw Thu, and Nyein Chan This section contains Supplementary Figures 1-3 and Supplementary Tables 1 and 2. NATURE GEOSCIENCE | www.nature.com/naturegeoscience 1 supplementary information DOI: 10.1038/NGEO558 Supplementary Fig 1. Fatalities from major cyclone events (> 10,000 deaths) from 1584 up to Nargis compiled from the Emergency Events Database (EM-DAT) and other sources (see refs. S1-S3) with storm track and wind speed (from the Joint Typoon Warning Center and IBTrACS) compared against 2004 Indian Ocean tsunami deaths (ref. S1). Additional cyclone track: 2006 Cyclone Mala with 22 deaths in Myanmar. 2 NATURE GEOSCIENCE | www.nature.com/naturegeoscience DOI: 10.1038/NGEO558 supplementary information (a) (b) (c) Supplementary Fig. 2. Field survey: (a) bark damage and (b) rafted debris in trees as high water marks at Pyinsalu; (c) vertical erosion on palm tree roots at Aung Hlaing. (a) (b) (c) (d) Supplementary Fig. 3. Coastal erosion: (a) Drinking water wells scoured in surf zone at Aya; Supplementary Fig 1. Fatalities from major cyclone events (> 10,000 deaths) from 1584 up to Nargis (b) Golden Buddhist Stupa built on land piercing the water surface offshore highlighting 150m compiled from the Emergency Events Database (EM-DAT) and other sources (see refs. S1-S3) with storm land loss. Land use: (c) Deforestation of mangroves for use as charcoal and rice paddies; track and wind speed (from the Joint Typoon Warning Center and IBTrACS) compared against 2004 Indian (d) Secondary growth mangroves with cyclone damage in a forestry reserve.