The first clouds are thin, wispy cirrus, followed by sheets of cirrus and cirrostratus and altostratus.
最开始的云石薄而缥缈的卷云,紧接着是成片的卷层云和高层云。
When cirrostratus clouds are disturbed by planes or strong winds, the droplets can freeze instantly or evaporate, the latter of which will form the hole.
当卷层云受到飞机或强风的干扰时,水滴会立即冻结或蒸发,若为蒸发就会形成孔洞。
These clouds occur within cirrostratus clouds, which are often composed of ice crystals and drops of water that are below freezing temperature but still in liquid form.