Tropical Cyclone Winston CoastalInundation

Transcription

1 Tropical Cyclone Winston CoastalInundation Cyprien Bosserelle, Herve Damlamian, Zulfikar Begg, MereoniKetewai, Deepika Lal, ArietaNavatoga, Joy Papao, Keleni Raqisia, Jens Kruger

2 STAR Conference Tropical Cyclone Winston Coastal Inundation Cyprien Bosserelle, Herve Damlamian, Deepika Lal, Jens Kruger

3 Tropical Cyclone Winston wiki Summary of impact Human 44 Casualties 50,000 people in evacuation centers 350,000 people affected (~40% of Fiji pop.) Infrastructures ~30,000 homes destroyed 7 Ferries wrecked/stranded 240 schools severely damaged/destroyed Highest winds 10-minute sustained: 233 km/h (145 mph) (Gust: 306km/h) 1-minute sustained: 285 km/h (180 mph) Lowest pressure 929 hpa(mbar); Economy FJ$2.0 billion Loss FJ$0.5 billion Damage 80% of the loss is from Agriculture 80% of the nation without power

4 Winston Landfall Vanua Levu Taveuni Viti Levu Koro Ovalau Vanuabalavu Source: Fiji Meteorological services

5 Summary of damages Human 44 Casualties 50,000 people in evacuation centers 350,000 people affected (~40% of Fiji pop.) Most Tragic Natural disaster in Fiji since 1979 At least 16 death by drowning in sea water ~30 death can be attributed to in sea water inundation Infrastructures ~30,000 homes destroyed 7 Ferries wrecked/stranded 240 schools severely damaged/destroyed Economy FJ$2.0 billion Loss FJ$0.5 billion Damage 80% of the loss is from Agriculture 80% of the nation without power

6 Cyclone damages from inundation Vanua Levu(Tacilevu) Koro (Nacamaki) Ovalau(OHR)

7 Cyclone damages Orion Aerial Survey, Nacamaki, Koro

8 Cyclone damages Orion Aerial Survey, OHR, Ovalau

9 Cyclone damages Tacilevu, Vanua Levu

10 Post-inundation survey: March 2016 Low tech, light weight Collect data on run-up, flow depth, inundation extent and building damages 1 week long survey 2 teams of 4 staffs 21 villages/settlements in Ovalau 26 Villages/settlement on Vanua Levu 446 Building assessed in Ovalau

11 Cyclone damages from inundation Ovalau Tokou

12 Ovalau map Tokou

13 Inundation maps: Tokou Damages: None ; Minor ; Moderate ; Severe ; Destroyed ;

14 Ovalau maximum runup

15 Ovalau maximum inundation extent

16 Theory for explaining the RU spatial variability

17 Cyclone damages from inundation Vanua Levu Tacilevu

18 Inundation Maps: Tacilevu Ocean inundation occurred (peaked) 1 hour before the river started to flood the village

19 Vanua Levu maximum runup

20 Vanua Levu maximum inundation extent

21 TC Winston wind, wave, model For Wind Nerds: JTWC best track Young & Sobeywind model For Storm Surges Nerds: Delft3D DFLOW FM 2 drag breakpoints Uncoupled (no wave force) For Wave Nerds: SWAN WESTH Cdcap=0.002

22 Maximum Storm tide

23 Maximum Wave height

24 Theory for explaining the RU spatial variability Storm Surge inundation Storm surge driven inundation

25 Summary Runup Inundation maps for 50 villages/settlements Up to 5.6m above highest tide of 2015 in Ovalau Up to 2.6mabove highest tide of 2015 in Vanua Levu Koro could not be covered by the survey Lightweight and Lowtech Lightweight survey allowed for fast coverage Low tech (dumpy level, staff) has low resource need Outcomes Inundation maps will be used for community awareness work (May also be used in relocations) This data will serve as a validation for the design of inundation forecasts Future improvement Visit to Koro Test wind solution Direct run-up simulation