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
Fujita scale and the wind speeds associated with the damage listed aren't rigorously verified. The Enhanced Fujita Scale was formulated due to research which suggested that the wind speeds required to inflict damage by intense tornadoes on the Fujita scale are greatly overestimated. A process of expert elicitation with top engineers and meteorologists resulted in the EF scale wind speeds, however, these are biased to United States construction practices. The EF scale also improved damage parameter descriptions. The original scale as derived by Fujita was a theoretical 13-level scale (F0–F12) designed to smoothly connect the Beaufort scale and the Mach number scale.