Around 90 people are being evacuated from their homes on the River Stour near Bournemouth.
Police began evacuating residents of the Ilford Bridge Home Park shortly after 3am following a severe flood warning from the Environment Agency.
They were being taken to the Boscombe Day Centre in Owl Road, Boscombe, Dorset Police said.
Officers have been monitoring the levels of the River Stour closely for the last 24 hours and people living in the threatened areas were warned of the possibility of flooding and evacuation.
Police described the efforts the rescue effort as a "multi-agency operation", and advised people who have concerns about flooding to contact the Environment Agency (EA).
Emergency services are also making ready to evacuate people from the Beaulieu Garden Park Home in Christchurch, Dorset, after t he EA issued another severe flood warning - warning of danger to life - at 5.40am, the third such alert in place.
Dorset Police said 15 residents were being moved from the Beaulieu park to the Boscombe Day Centre.
Thousands of people face a cold and wet Christmas after storms caused widespread flooding and power failures across the UK.
Scores of homes have been left under water and tens of thousands will endure a Christmas Day without electricity after torrential rain lashed the country.
The Coastguard rescued 76 people from a caravan park that was flooded by the River Medway at Yalding in Kent last night.
Travellers trying to get home on Christmas Eve also battled treacherous conditions on the roads and suffered major delays as the rail network was brought to its knees.
There was chaos at Gatwick Airport in West Sussex after a power cut at the North Terminal led to cancellations and delays, leaving thousands of passengers stranded. The airport said last night normal service would resume today.
Five people have have also died in the last three days because of the violent weather.
The Coastguard, operating outside its area of jurisdiction, joined Kent Fire and Rescue to rescue people from the Little Venice Caravan and Marina Park in Yalding after rising waters from the River Medway cut them off.
Rescuers checked caravans and helped residents to leave by boat and 4x4 vehicles.
By 8pm the water was chest deep, the Coastguard said, and a helicopter was brought in as a precaution while the last 21 people were led to safety from rising flood waters and listing caravans.
Once on dry land the Salvation Army took them to a local leisure centre.
Around 75,000 homes across the UK are still without power, the Energy Networks Association said, and engineers were working through the night to get provision running for Christmas Day.
The EA said that by last night 150 properties had been flooded in England, mainly in the south and focused in Surrey and Kent, with numbers expected to rise.
Firefighters in the two counties broke a five-hour nationwide strike last night to help deal with the effects of the storms.
In Surrey residents were evacuated from their homes in Dorking, Leatherhead and Guildford, while more evacuations occurred in Tonbridge, Kent.
Some 40 properties were evacuated in Godalming because of concerns over the height of the River Wey, Surrey Police said, and a rest centre was set up for residents.
In the Mole Valley evacuations took place in Leatherhead and Dorking after the River Mole burst its banks in several areas.
Police said the Flanchford Bridge over the River Mole near Reigate had collapsed, but no one was injured.
A severe flood warning, warning of danger to life, remains in place for the river at Leatherhead and Fetcham in Surrey after it rose to record-breaking levels late last night. Levels are now beginning to fall, the EA said.
Roads were also closed in Guildford and Old Woking in Surrey, police said. Surrey Fire and Rescue said last night that it was dealing with "many rescues" because of the flooding.
The EA this morning had almost 130 flood warnings across England and Wales, mainly in the South East, the South West and the Midlands. A further 226 flood alerts were also in place, with 90 in the South East alone.
The flooding will leave Christmas cancelled for many people. Gary Button, manager of the Old Mill Hotel in Batheaston near Bath, told the BBC he had to cancel more than 50 Christmas dinners after the River Avon flooded the property.
Thousands of people have had their Christmas plans ruined by the storms, and many face the festive period without power.