They rarely seem to form the traditional anvil shape but are very solid-looking and move and form fast.
We have had daily thunderstorms. Most days start with clear blue skies then clouds like the ones here barrel up over the mountains and spread out into general cloud cover, at which point it gets very noisy and the rain is amazing - one day it filled the water butt in one 'shower'. There are, of course, strong gusts of wind as the storms sweep in, but it is mostly very opressive. I meant to get the clouds at a different stage but the day I saw them my camera battery ran out at the wrong moment.