The extreme waves that batter the Irish coast

Would you know a storm wave from a tsunami? Or a rogue wave from a surfer's wave? A new paper out this week in Natural Hazards and Earth Systems Sciences describes more than 50 historical extreme-wave events in Irish waters, stretching out to the Continental Shelf and back in time to the turn of the last ice age.

Trawling through sources such as buoy data, lighthouse and tsunami records, scientific and media reports and even stories of legend, the researchers looked to classify the events as storm waves or surges, tsunamis or more localised and unpredictable “rogue” waves.

Evidence is pretty thin on the ground for extreme wave events that may have happened many hundreds or even thousands of years ago. But more recent eyewitness accounts and records chart some whoppers, including a huge wave that this week in 1861 damaged a lighthouse at an impressive 67 metres or so above sea level on the Mullet Peninsula in Co Mayo.

Plenty of mysteries remain, including a 12-metre wave in Galway Bay in 1894, which hit the SS Diamond as it was waiting to enter port.

"We have discarded the tsunami interpretation but we do not know which type of wave it was that hit the SS Diamond that day," says researcher Prof Frédéric Dias from University College Dublin's school of mathematical sciences.

“Overall what stood out from our look at extreme wave events is that we are now convinced there are more rogue waves off the west coast than anticipated, and that phenomenal sea states and swell do occur.”

Prof Dias would welcome more information about historical waves at frederic.dias@ucd.ie