Cumulonimbus and aviation at this altitude, updraughts with speeds that can exceed . Such an updraught speed corresponds to the wind speed of a small hurricane. The speed can even exceed . The maximum number in the Beaufort scale is 12 ("hurricane force" wind) and is assigned to wind speeds of 64 knots or greater. If the Beaufort scale were extended, these updraughts would have a Beaufort number of 14 "in the vertical direction". The turbulence is then "extreme" at this altitude. Moreover, the diameters of the updraught columns vary between 2 km (air mass thunderstorm) and 10 km (supercell thunderstorm). The height
MS Estonia starboard because of poor cargo distribution. According to the final disaster report, the weather was rough, with a wind of , force 7–8 on the Beaufort scale and a significant wave height of compared with the highest measured significant wave height in the Baltic Sea of . Esa Mäkelä, the captain of "Silja Europa" who was appointed on-scene commander for the subsequent rescue effort, described the weather as "normally bad", or like a typical autumn storm in the Baltic Sea. All scheduled passenger ferries were at sea. The official report says that while the exact speed at the time of