Multiscale Dynamics of Bathymetry-Driven Extreme Wave Breaking
Abstract
Belharra, a wave-energy hotspot located on the French Basque coast, is renowned for occasionally presenting world-class big-wave surfing conditions. This study investigates the underlying processes leading to exceptionally large waves breaking at this site, treated here as a natural case study for bathymetry-driven wave-energy focusing. A combination of spectral and phase-resolving numerical modeling is used to examine a range of incident swell conditions and tide levels, revealing the key processes that shape the wave field at both coastal and local scales. A wave-by-wave analysis of high-energy scenarios is complemented by qualitative comparisons with surfer trajectory data recorded during a large swell event, while coastal hindcasting is used to study historical large swell events. The findings show that extreme conditions at Belharra result from multi-scale bathymetric focusing, in which coastal-scale refraction over offshore features preconditions the incoming swell, while local shoaling over the seamount triggers depth-induced breaking. The most energetic conditions occur for long-period swells approaching from a narrow directional window. Within this window, maximum wave-height amplification and maximum breaking intensity occur for different incident directions, near 295 • and 315 • , respectively. In addition, higher tide levels lead to larger wave heights but reduced breaking intensity. These findings improve our understanding of the wave dynamics at Belharra and provide broader insight into bathymetry-driven wave-energy concentration and extreme breaking in coastal environments.
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BibTeX
@article{slamovitz2026multiscale,
title = {{Multiscale Dynamics of Bathymetry-Driven Extreme Wave Breaking}},
author = {Diego Slamovitz and Matthias Delpey and Denis Morichon and Stéphane Abadie and Assaf Azouri and Mario Morales-Hernández and Volker Roeber},
journal = {Water Waves},
year = {2026},
month = oct,
doi = {10.1007/s42286-026-00151-y},
url = {https://hal.science/hal-05774667v1},
note = {CC BY-SA 4.0},
}
RIS
TY - JOUR
TI - Multiscale Dynamics of Bathymetry-Driven Extreme Wave Breaking
AU - Diego Slamovitz
AU - Matthias Delpey
AU - Denis Morichon
AU - Stéphane Abadie
AU - Assaf Azouri
AU - Mario Morales-Hernández
AU - Volker Roeber
PY - 2026
DA - 2026/10/01
JO - Water Waves
DO - 10.1007/s42286-026-00151-y
UR - https://hal.science/hal-05774667v1
AB - Belharra, a wave-energy hotspot located on the French Basque coast, is renowned for occasionally presenting world-class big-wave surfing conditions. This study investigates the underlying processes leading to exceptionally large waves breaking at this site, treated here as a natural case study for bathymetry-driven wave-energy focusing. A combination of spectral and phase-resolving numerical modeling is used to examine a range of incident swell conditions and tide levels, revealing the key processes that shape the wave field at both coastal and local scales. A wave-by-wave analysis of high-energy scenarios is complemented by qualitative comparisons with surfer trajectory data recorded during a large swell event, while coastal hindcasting is used to study historical large swell events. The findings show that extreme conditions at Belharra result from multi-scale bathymetric focusing, in which coastal-scale refraction over offshore features preconditions the incoming swell, while local shoaling over the seamount triggers depth-induced breaking. The most energetic conditions occur for long-period swells approaching from a narrow directional window. Within this window, maximum wave-height amplification and maximum breaking intensity occur for different incident directions, near 295 • and 315 • , respectively. In addition, higher tide levels lead to larger wave heights but reduced breaking intensity. These findings improve our understanding of the wave dynamics at Belharra and provide broader insight into bathymetry-driven wave-energy concentration and extreme breaking in coastal environments.
SN - 2523-367X
SN - 2523-367X
ER -