NH24A-01
Tropical cyclone Pam coastal impact survey in Vanuatu

Tuesday, 15 December 2015: 16:00
309 (Moscone South)
Hermann M Fritz1, Jessica Pilarczyk2,3, Thomas Jaroslaw Kosciuch4, Isabel Hong2, Allan Rarai5, Morris J Harrison5, Fred R Jockley5 and Ben Horton3,6, (1)Georgia Institute of Technology Main Campus, Atlanta, GA, United States, (2)Institute of Marine and Coastal Science, New Brunswick, NJ, United States, (3)Earth Observatory of Singapore, Singapore, Singapore, (4)University of Southern Mississippi, Stennis Space Center, MS, United States, (5)Vanuatu Meteorology and Geo-Hazards Department, Port Vila, Vanuatu, (6)Rutgers University New Brunswick, Marine and Coastal Sciences, New Brunswick, NJ, United States
Abstract:
Severe tropical cyclone Pam (Cat. 5, SSHS) crossed the Vanuatu archipelago with sustained winds of 270 km/h on March 13 and 14, 2015 and made landfall on Erromango. Pam caused the worst natural disaster in Vanuatu’s recorded history since severe tropical cyclone Uma in 1987. Eleven fatalities were directly attributed to cyclone Pam and mostly due to lack of shelter from airborne debris. On March 6 Pam formed east of the Santa Cruz Islands and intensified while tracking southward along Vanuatu severely affecting the Shefa and Tafea Provinces. An international storm surge reconnaissance team was deployed to Vanuatu from June 3 to 17, 2015 to complement earlier local surveys. Cyclone Pam struck a remote island archipelago particularly vulnerable to the combined cyclonic multi-hazards encompassing extreme wind gusts, massive rainfall and coastal flooding due to a combination of storm surge and storm wave impacts. The team surveyed coastal villages on Epi, the Shepherd Islands (Tongoa and Mataso), Efate (including Lelepa), Erromango, and Tanna. The survey spanned 320 km parallel to the cyclone track between Epi and Tanna encompassing more than 45 sites including the hardest hit settlements. Coastal flooding profiles were surveyed from the shoreline to the limit of inundation. Maximum coastal flood elevations and overland flow depths were measured based on water marks on buildings, scars on trees, rafted debris and corroborated with eyewitness accounts. We surveyed 91 high water marks with characteristic coastal flood levels in the 3 to 7 m range and composed of storm surge with superimposed storm waves. Inundation distances were mostly limited to a few hundred meters. Coral boulders of more than 1 m diameter were measured on Erromango and sediment samples were collected at key sites across the archipelago. Infrastructure damage on traditional and modern structures was assessed. Eyewitnesses were interviewed at most sites to document the chronology of the wind and coastal flooding events, survival strategies, cyclone and tsunami awareness, evacuation procedures, shelter locations and ancestral knowledge. The measured cyclone Pam high water marks will facilitate the interpretation of the collected sedimentary evidence and serve as benchmarks for modeling studies.