Ireland makes waves on a global scale as seven-storey swell recorded off coast of Cork

Irish Independent

08-06-2025

Data released by the Marine ­Institute shows the 21.9-metre wave was captured by the M3 weather buoy, 56km south-west of Mizen Head at 10am on January 27, making it one of the largest waves ever logged in Irish waters.
'That wave was recorded during Storm Éowyn as it passed over Ireland. The M3 buoy is located approximately 55km offshore west-southwest of ­Mizen Head, Co Cork, the southernmost point of Ireland,' said Alan Berry, research infrastructure manager at the Marine Institute.
But the towering swell off the Cork coast pales beside two freak waves that breached the 30-metre mark over the past decade.
A record-breaking rogue wave measuring 32.3m was recorded five years ago, nearly 400km off the Galway coast by the M6 buoy stationed in the deep Atlantic, according to the Marine Institute.
It remains the largest confirmed wave ever measured in Irish waters, although an unverified larger swell was logged 11 years ago.
'Analysis of raw data from a wave rider buoy operated by ESB at Killard, Co Clare, suggested that a 33.96m wave was recorded on January 26, 2014,' Mr Berry said.
'The accuracy of that observation has never been verified and should be treated with caution due to the depth of water [39m] and the stated operating range of the wave monitoring buoy.
'A number of verified rogue waves were recorded by the buoy in the following two days, including the 'Killard Wave' measuring 26.45m and a number of other waves in excess of 20m.
'But, to the best of our knowledge, the 32.3m wave recorded at the M6 buoy in 2020 is the largest recorded wave ever in Irish waters.'
Ireland's exposed position on the storm-tossed track of North Atlantic low-pressure systems gives rise to some of the most colossal seas on the planet
Closer to land, a 30.96m wave was measured by a weather buoy 10 miles off the coast of Belmullet in the westerly tip of Mayo just after midnight on March 2, 2016. The same buoy recorded a 26.35m rogue wave the following night at 3am.
Mr Berry said the Belmullet coast ­experiences some of Ireland's tallest waves because it lies close to the edge of the continental shelf, where the relatively shallow coastal waters — around 250 metres deep — drop sharply into the deep ocean, which plunges to about 3,000 metres.
Ireland's exposed position on the storm-tossed track of North Atlantic low-pressure systems gives rise to some of the most colossal seas on the planet.
Rogue waves — steep, solitary swells that rise at least twice as high as the surrounding sea — were once thought to be maritime myth, but are now well-documented.
According to researchers, between one in every 10,000 and one in every 30,000 waves fall into this rare category.
The data from the Marine Institute also showed these waves aren't confined to the open Atlantic, with giant waves occurring in sheltered waters, including off the Connemara coast this winter.
'The largest wave ever recorded in Galway Bay occurred during Storm Éowyn, measuring 10.1m in a depth of water of 25m just off the coast of Spiddal village,' Mr Berry said.
The Marine Institute's real-time monitoring network provides insight into how often — and how close to shore — these extreme waves can appear. Ireland's Atlantic-facing coastline places it at the front line of North ­Atlantic swell systems, making it one of Europe's most wave-battered regions.