A North American low-pressure system moved east and combined with another cyclone in the Western Atlantic. This system moved into an area off the coast of Ireland that already had high waves owing to a series of strong systems the previous week. In addition, a strong anticyclone over the Azores created a large pressure gradient in the North Atlantic that directed a strong fetch towards Ireland. There was also an extended fetch length in the North Atlantic in the direction of Europe while the swell was created. These combined conditions produced waves that were confirmed by satellite data on 7 March 2012 to have exceeded in height.