A huge low extending for over a 1000 miles of ocean pointing at Ireland and Scotland generated this swell. Crucially a phenomena known as the Greenland Jet Tip exaggerated the initial storm's power creating a swell which peaked around the 27ft at 17 second mark. A huge swell by any standard. "Checking the records we’re looking at storms in the size range about 5 times in a decade. Ignore the ones arriving with storm force winds and you’re talking about 3 times a decade historically." says forecaster, Ben Freeston.