If you see a cloud with a tail hanging from it, then you may be looking at the cloud feature known as virga. You can think of this as precipitation that dissipates away before it reaches the ground.

The cloudy tails in these Altocumulus virga spotted by Bruce Harwood (Member 56,179) over Guerneville, California, US look to be made of ice crystals. These are sublimating – changing directly from solid ice to gas (known as water vapour) – as they fall through the likely drier and warmer air beneath. Bruce couldn’t decide whether the smaller cloud below was a woodpecker chick being brooded by its mother or a small spacecraft returning to its mothership. ‘Either way,’ he concluded, ‘the clouds are related, and motherhood is involved.’