Typical case of narrow tube effect

On February 28th, 2007, the 5807 passenger train from Urumqi to Aksu was hit by a strong wind of 13, which derailed the vehicle and caused casualties. The southern Xinjiang line was forced to stop for 9 hours. 13 wind is a hurricane with a wind speed of about 37 meters per second. With the cooperation of certain weather system and local terrain, the train may be overturned by strong wind.

2065438+00 From 5: 00 on April 24th to 5: 00 on 25th, there were 6-7 gale in southern and eastern Xinjiang, northern and western Qinghai, Gansu, western Inner Mongolia and Ningxia. In some areas, the instantaneous wind force reached 8-9, accompanied by dusty weather, and sandstorms occurred in some areas, including strong sandstorms or extremely strong sandstorms in some areas of Gansu, Gansu Minqin 19 on the 24th.

20 13 at 4 o'clock in the afternoon on April 6, a girl was "blown" by the strong wind while walking in downtown Hangzhou. "I just got blown up by the wind, and my feet were off the ground. Interview Ben flew together ... I said it was a magical experience." Holding an interview book, she is crossing West Lake Avenue from south to north near Hangzhou Railway Station: "Because the green light is about to turn red, I am in a hurry to cross the road. It is the moment when your feet are alternately raised, and I feel that the whole person is off the ground. " Recalling the situation at that time, she said that she was "blown up by the wind" not the kind that everyone understood, but had an obvious feeling that her feet were off the ground. The girl is 1.55 meters tall and weighs about 84 kg. Nothing like this has ever happened to her.

Due to the narrow tube effect caused by topography, the near-surface wind speed in Hexi area of Gansu Province has obviously increased, and there have been strong sandstorms or extra-strong sandstorms in Hexi area. From March to May every year, Mongolian cyclones are active and cold air activities are frequent, which is easy to produce windy weather; Less rain, warmer weather and higher temperature in desert areas are easy to cause sandstorms.