Wind Causes Accidental Vertical Takeoff

Have you ever seen how wind causes accidental vertical takeoff? The plane was secured with ropes, but still managed to get airborne, because of really strong wind. This accident occurred in Gelendzhik, Russia. You may have seen military planes doing vertical takeoff, but seems like not only high end jets can do it. That is why every plane is tied down to the ground, because wind as strong as 20 m/s, should be able to send small airplane airborne. You may see in the video, that the plane was tied with ropes, but this security measure was not enough to secure the plane. Was it a human error? Should it have been secured better? or was is an unexpected gust of wind? Do you know any other examples when wind causes accidental vertical takeoff?