Herakles (pusher) the fuel supply and lubrication system due to the violent pitching of the vessel were not ruled out. On 2 March 2004 the weather in the Bothnian Sea gradually developed into a force 10 storm on the Beaufort scale, with average wind speed around and gusts exceeding . At midnight, shortly before "Herakles-Bulk" sank, the ten-minute average at Svenska Högarn was with three-second gusts of almost . The freezing temperatures combined with strong wind and high waves resulted in fast icing of the ship structures. In 1992 the Finnish Maritime Administration issued a wind limit of for "Herakles" due to
Beaufort Gyre in the Arctic Ocean; the majority of the Arctic's freshwater supply originates from Russian rivers as runoff. The clockwise circulation of the Beaufort Gyre is induced by the wind patterns associated with the permanent anticyclonic high pressure system over the western part of the Arctic. In a clockwise-rotating gyre in the Northern Hemisphere, the Coriolis force causes the ocean water to flow inward toward the gyre's center where it accumulates, effectively forming a dome of water. If the wind patterns shift into a cyclonic circulation due to the residence of a low pressure system (rising air induced by warmer ocean