Royal Air Force Sea King helicopters, inshore life boats and fire service rescue boats are in attendance at the Riverside Caravan Park in Llandre, Bow Street, near Aberystwyth, where "numerous people" need help.
There is a large amount of water and a heavy current running through the caravan park.
Parts of Britain are braced for more flooding as a "once-in-50-years storm" is set to hit the south-west and Wales.
The South East and mid Wales have been worst hit by the rain which has battered Britain. The rain is set to continue.
Flooding and heavy rain hit many areas across Britain today, with the Environment Agency issuing further flood warnings.