In England, the worst affected area is the north east where a metre of snow has fallen.
In a village near Sheffield in Yorkshire, 100 people had to sleep in a church because their cars got stuck in the snow.
Airports like Gatwick near London and Edinburgh are closed - and won't be opening until at least Friday morning.
The big freeze is affecting sports fixtures too. In rugby Bath's trip to Newcastle couldn't happen yesterday because of a frozen pitch, and in football all six SPL matches aren't looking likely to go ahead.