Storm Ophelia: Biggest wave ever recorded off Irish coast during weather phenomenon

Ralph Riegel

The sheer scale of Hurricane Ophelia's power was underlined by a weather buoy registering the biggest wave ever recorded off the Irish coast.

The Irish Weather Buoy Network (IWBN) confirmed it recorded one individual wave off Waterford which reached a startling height of 17.81m (58.4 feet), almost the height of a six-storey building.

Put in context, that is roughly one sixth the height of Dublin's Spire which stands at 121m.

At the peak of Hurricane Ophelia's fury, Fastnet recorded one gust which reached 190kmh.

The IWBN confirmed the record wave at 4pm on Monday by the M5 buoy off the south east coast.

Unsurprisingly, the M5 buoy shortly afterwards was ripped from its moorings and had to be subsequently recovered by the MV Puffin in an operation co-ordinated by the Marine Institute.


Such was the power of Hurricane Ophelia off the Irish coast that M5 was one of five individual buoys ripped from their moorings during the storm.

"The weather buoy network, which is managed by the Marine Institute, provides further vital atmospheric (including wind speed) and oceanographic information to support both maritime safety and, importantly in storm events such as Ophelia, help to validate the weather forecast models run by Met Éireann providing guidance to the national emergency planning efforts," a Marine Institute spokesperson explained.

However, while giant by the normal standards of Irish coastal waves, the Waterford wave last Monday was not the biggest in ocean history.

In 2011, a 20.4m monster wave was recorded some 100km away from Donegal, at the height of a Force 10 gale.

Last December, an offshore weather buoy between Ireland, Iceland and Britain recorded a monster 19m wall of water.

The wave smashed the previous record holder - one of 18.275 metres (59.96ft) measured in the North Atlantic in December 2007.

Taller than a six-storey building, the wave occurred after a "very strong" cold front had barrelled through the area, producing winds up of 43.8 knots (80kmh).


Meanwhile, ten of thousands of customers remain without telecommunications throughout the country.

eir estimates that the number of customers without broadband, telephone and mobile service as a result of Storm Ophelia has now reduced to 50,000.

There are over 1,000 different locations across the country where we have sustained network damage. The scale of the damage ranges from a single pole, up to 18 poles and two kilometres of cables along one particular section of road. The vast majority of impacted mobile sites are now back in service.

The southern half of the country continues to be the worst affected area. The counties with the highest amount of customers without service are:  Cork (15,980); Wexford (6,112) and Limerick (3,965).