The southwest coast of England was subjected to an unusually energetic sequence of Atlantic storms during the 2013/2014 winter, with the 8-week period from mid-December to mid-February representing the most energetic period since at least 1953. A regional analysis of the hydrodynamic forcing and morphological response of these storms along the SW coast of England highlighted the importance of both storm-and site-specific conditions.The key factor that controls the Atlantic storm wave conditions along the south coast of southwest England is the storm track. Energetic inshore wave conditions along this coast require a relatively southward storm track which enables offshore waves to propagate up the English Channel relatively unimpeded. The timing of the storm in relation to the tidal stage is also important, and coastal impacts along the macro-tidal southwest coast of England are maximised when the peak storm waves coincide with spring high tide. The role of storm surge is limited and rarely exceeds 1 m.The geomorphic storm response along the southwest coast of England displayed considerable spatial variability; this is mainly attributed to the embayed nature of the coastline and the associated variability in coastal orientation. On west-facing beaches typical of the north coast, the westerly Atlantic storm waves approached the coastline shore-parallel, and the prevailing storm response was offshore sediment transport. Many of these north coast beaches experienced extensive beach and dune erosion, and some of the beaches were completely stripped of sediment, exposing a rocky shore platform. On the south coast, the westerly Atlantic storm waves refract and diffract to become southerly inshore storm waves and for the southeast-facing beaches this results in large incident wave angles and strong eastward littoral drift. Many south coast beaches exhibited rotation, with the western part of the beaches eroding and the eastern part accreting.

No abstract

No abstract

No abstract

No abstract

No abstract

Rip currents are strong, narrow seaward-flowing currents in the surf zone and are common on energetic sandy beaches. They are generally associated with distinct beach morphology, comprising nearshore sand bars and channels, and represent a real natural hazard to surf zone users. Rip current circulation is primarily driven by spatial gradients in wave breaking and water levels in the surf zone, which in turn are controlled by beach morphology, o↵shore wave conditions and tidal level. These factors, which are highly variable over hours (tides), days (waves) and weeks (morphology), also control the rip risk to bathers. However, the precise roles of these di↵erent environmental factors in controlling rip dynamics on meso-to macro-tidal beaches is not exactly known and thresholds separating di↵erent types of rip circulation and flow strengths, and hence rip risk, have not been quantified. Here, analysis of 5-year lifeguard incident records from 20 beaches in southwest England showed that high-risk, high-exposure scenarios for bathers occur disproportionately around mean low water on days with low wave height (H s < 1 m), long wave period (T p > 10 s), shore-normal wave approach and light winds (> 5 m s 1). Detailed in-situ Lagrangian field measurements of rip currents collected on 23 di↵erent days from Perranporth Beach, UK identified waves (characterised by H s T p) and active morphology (characterised by tidal elevation) as the key controlling factors determining the mode of rip behaviour. Maximum hazard was associated with the combination of maximum rip exits and rip flow speeds. These conditions occurred when H s T p was at or just below average values and when those waves were acting on the active morphological template, around mean low water. The thresholds in wave conditions and tidal elevation identified here were e↵ective in discriminating between observed coast-wide high-risk incident events, illustrating that such mass rescue events have a considerable element of environmental control. Because many beaches along the west coast of southwest England are characterised by nearshore bar morphology just below the mean low water level, and are a↵ected by similar wave and tide conditions, the results obtained from this beach are transferable to other locations. The findings of this study may also have implications for other beaches with nearshore bar-rip morphology at specific tidal levels.

No abstract