Is there really a strong wind of 12 on June 6th in Yanjianli, Hubei Province?

Zhang Zuqiang, Director of Emergency Disaster Reduction and Public Service Department of China Meteorological Bureau, just said at the press conference of China Meteorological Bureau: For the shipwreck accident, it is not certain that there is a tornado, but it is certain that there is strong convective weather. China Meteorological Bureau has formed an expert group to rush to Hubei to further analyze and judge whether there is a tornado.

On the evening of June 1, a cruise ship of the Yangtze River with 456 people was overturned by a tornado in Jianli section of the Yangtze River in Hubei Province. According to reports, the relevant person in charge of the Yangtze River Maritime Safety Administration said that the "Oriental Star" large luxury cruise ship was suddenly hit by a tornado, overturned and detained in the water within a minute or two. At that time, most people on board were ready to rest, so there was no distress signal on board when the accident happened.

The Central Meteorological Observatory released a message earlier. According to the analysis of meteorological radar monitoring data, the reason for the capsizing of the ship was a tornado, and the wind force was above 12. Zhu, former chief researcher of climate impact assessment of the National Climate Center, told Caixin reporter that the tornado itself is a small-scale and low-probability event, which is difficult to predict.

Zhu said that generally speaking, the occurrence of tornadoes is related to thunderstorms and strong convective weather, but it is accidental and impossible to predict at a fixed time. The path of a tornado is a very narrow line. "The path has a certain relationship with the terrain and may follow the canyon." He said that it can only be said that this tornado only passed through the strait. The warning can only go so far.

According to the analysis of radar monitoring data of the Central Meteorological Observatory, after 20: 00 on June 1 day, a ribbon thunderstorm echo passed through Jianli County from west to east. The strongest echo observed by radar is at the southwest of Jianli15km, with intensity of 50dB, echo height of 7-9km and moving speed of 30-40km/h..

Tornado is a strong, small-scale air vortex, the scale is generally around 100 meters, and it is often produced by strong air convection under extremely unstable weather conditions. Its wind power can reach more than 12, and the ground wind speed of the strongest tornado is between 1 10 m/s and 200m/s.

Qiao Lin, former chief forecaster of the Central Meteorological Observatory, told Caixin reporter that the tornado happened suddenly, that is, a few minutes later, the phenomenon of "dragon sucking water" could be seen on the water. Its life span is short and it develops rapidly, and the United States often suffers huge losses due to tornadoes. Tornadoes occur quickly, with irregular paths and small areas. Usually it is produced under strong convective clouds and cumulonimbus clouds. The wind is strong, sudden, irregular and unpredictable.

When a tornado occurs, there is always a funnel-shaped cloud column with a diameter from tens of meters to hundreds of meters hovering from the bottom of the convective cloud. Some winds that can reach the ground and cause disasters on the ground are called tornadoes; Some do not reach the ground or produce disastrous winds on the ground, which is called air funnel; Some reach the surface and are called waterspouts. Tornadoes are very powerful, which can cause crops and trees to be destroyed instantly, traffic and communication to be interrupted, houses to collapse, human and animal casualties and other heavy losses.

Qiao Lin said that tornadoes were monitored at home and abroad, but the scope was very small and short-lived. Early warning is almost impossible and can only be seen with the naked eye. If you see the cloud stranded, observe its moving direction and leave quickly along the direction perpendicular to the moving direction. "This accident happened at night and had a great impact on observation."

In fact, the probability of a tornado in China is very small. Tornadoes that occur every year can be calculated in single digits, and there are even fewer waterspouts. Zhu said that the tornado on the Yangtze River is a small probability event.