Magnitudes of nearshore waves generated by tropical cyclone Winston, the strongest landfalling cyclone in South Pacific records. Unprecedented or unremarkable?

• Published in: Sedimentary geology Vol. 364; pp. 276 - 285
• Main Authors: Terry, James P., Lau, A.Y. Annie
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-02-2018
• Subjects: Coastal boulders; Cyclone Winston; Extreme waves; South Pacific; Tropical cyclones; Wave magnitude; Extreme waves; Cyclone Winston; South Pacific; Coastal boulders; Wave magnitude; Tropical cyclones
• ISSN: 0037-0738
• DOI: 10.1016/j.sedgeo.2017.10.009

We delimit nearshore storm waves generated by category-5 Tropical Cyclone Winston in February 2016 on the northern Fijian island of Taveuni. Wave magnitudes (heights and flow velocities) are hindcast by inverse modelling, based on the characteristics of large carbonate boulders (maximum 33.8 m3, 60.9 metric tons) that were quarried from reef-front sources, transported and deposited on coral reef platforms during Winston and older extreme events. Results indicate that Winston's storm waves on the seaward-margin of reefs fringing the southeastern coasts of Taveuni reached over 10 m in height and generated flow velocities of 14 m s−1, thus coinciding with the scale of the biggest ancient storms as estimated from pre-existing boulder evidence. We conclude that although Winston tracked an uncommon path and was described as the most powerful storm on record to make landfall in the Fiji Islands, its coastal wave characteristics were not unprecedented on centennial timescales. At least seven events of comparable magnitude have occurred over the last 400 years.
•Cyclone Winston (February 2016) was the strongest landfalling cyclone on record in the South Pacific.•On Taveuni island, Fiji, carbonate boulders up to 34m3 and 61tons were deposited on reefs.•Coastal waves reached over 10m in height and generated flow velocities exceeding 14ms−1.•Comparison is made between Winston, Tomas and prehistorical cyclones.•Geomorphological evidence suggests similar magnitude events over centennial timescales.