HURRICANE-style waves churned in the sea off the north coast yesterday morning as much of the Province lay in the grip of snow.
The sea state was described as “Phenomenal” – a technical term associated with hurricane-strength conditions.
Such extreme waves are only seen perhaps half-a-dozen times each year, according to Ryan Gray, watch officer with HM Coastguard.
It means wave heights from peak to trough would be at least 14 metres (46 feet) – roughly “the size of a house”, he added.
The areas covered by the sea state were Rockall (east Atlantic) and Malin (stretching from Larne to Stornoway and Donegal).
Shipping had to brave conditions described as “storm force 10” on the Beaufort scale (which reaches up to a maximum of 12), with wind speeds reaching in excess of 60mph over the choppy seas.
This remained the case until about 4pm, when the winds began to drop.
Meanwhile, the Irish Sea, covering the area south of Larne, was rated at the slightly lower “gale force nine”, and stayed more-or-less the same throughout the afternoon.
Mr Gray said: “Phenomenal’ is the maximum you can go to. I was quite surprised when it came in this morning. If you get a good spell of bad weather you could get it – but very, very rarely would you get ‘phenomenal’ wave height.
“Basically if a ship was hit by one of those waves, it could be damaged quite severely – a big, commercial ship.”
Nonetheless, while speaking to the News Letter at about 11.30am he could see five ships at sea in Malin and Rockall; three fishing vessels, one tanker and another cargo ship bound for Belfast
“All we can do is advise them what the forecast is, and it’s up to them,” he said.
At time of checking yesterday afternoon, the coastguard had no reports of vessels encountering trouble.
But it comes on top of a generally bad winter for fishermen, said Dick James, chief executive of the Northern Ireland Fish Producers’ Organisation.
Speaking from Portavogie, he said: “From a fishing perspective it’s a waste of time going out there when the weather’s so violent – you couldn’t get your fishing gear to work anyway.
“They’re all tied up in Portavogie today. Nobody’s putting their nose out at all. Nor would I advise them to.”
And, back on land, many Ulster residents were left contending with snow and slush yesterday morning.
Translink said there were problems due to snow with some of its Metro services in north and west Belfast yesterday morning, and Ulsterbus services suffered delays and had to change routes.
The Met Office recorded a depth of 9cm of snow (about 3.5 inches) lying at Glenanne, Co Armagh, at about 10am yesterday morning.
John Lee, from forecasting agency MeteoGroup, said today is likely to be warmer, with temperatures of about 5C.
The Met Office’s Sarah Holland agreed, adding that although it is still expected to be quite gusty (with 30mph winds predicted) conditions are unlikely to be as severe as yesterday.
Neither agency said there is much likelihood of more snow over the next few days.