Extraordinary boulder transport by storm waves (west of Ireland, winter 2013-2014), and criteria for analysing coastal boulder deposits

Quantifying CBD dynamics helps us understand the transmission of wave energies inshore during high-energy storm events. The transported boulders documented here are larger than many of those interpreted to have been moved by tsunami in other locations, which means that boulder size alone cannot be used as a criterion for distinguishing between tsunami and storm emplacement of CBD. The biggest blocks-up to 620 t-are new maxima for boulder mass transported by storm waves. We predict, however, that this record will not last long: the 2013-2014 storms were strong but not extreme, and there are larger boulders in these deposits that didn't move on this occasion. Bigger storms will surely move larger clasts, and clasts at greater distances from the shoreline. These measurements and relationships emphasise the extreme power of storm waves impacting exposed coastlines, and require us to rethink the upper limits of storm wave energy at coasts.