Curved tendrils hang downwards from the clouds. They are virga or fallstreaks. As here, they they are at their most spectacular when lit by the rays of a setting sun.
Virga are streams of raindrops, snowflakes or even halo forming ice crystals. They fall from the clouds but evaporate before reaching the ground.
Virga can be seen from all levels of cloud but more usually from medium level altocumulus, altostratus and from higher cirrus.
Fallstreaks are characteristically hook shaped. Differences in wind speed with height (wind shear) can be responsible.
Another factor is that as the water droplets or ice crystals evaporate and shrink they fall ever more slowly and finally drift horizontally with the wind.
|
