By Carolyn Cohn and Kate Holton
LONDON (Reuters) - Torrential rain and gale force winds battered northern Britain on Wednesday, cutting power to thousands of homes and forcing some to evacuate flooded streets in the third major storm in a month.
The Environment Agency said Britain had faced an extraordinary period of severe weather and flooding in December, with consultants PwC warning that the latest deluge from Storm Frank could take total losses above 3 billion pounds ($4.5 billion).
Further heavy rain was predicted to fall throughout Wednesday as the latest storm swept across northern England, Scotland and Northern Ireland, sparking warnings of more significant flooding.
A Chinook helicopter was being used to deposit sandbags. In the North Yorkshire town of Tadcaster late on Tuesday, part of an 18th century stone bridge crumbled into the racing river.
"The weather remains hugely challenging, with more rain threatening to cause further flooding in Cumbria and Yorkshire today and into New Year’s Eve," said Craig Woolhouse at the Environment Agency.
Around 6,700 properties were flooded in northern England in the last week as river levels reached all time highs, while three severe flood warnings remain in place, meaning there is a danger to life.
In Northern Ireland and the Republic, roads flooded, flights were delayed and thousands went without power while in Scotland, local media reports said people were being evacuated from their homes in the north east town of Ballater by dingy.
PwC on Wednesday raised its estimate of insured losses from two earlier storms - Desmond and Eva - to between 900 million pounds and 1.2 billion pounds from an earlier range of 700 million to 1 billion pounds.
"The storms this time have generated a far greater proportion of non-insured losses compared to the total economic damage," said Mohammad Khan, general insurance leader at PwC, in a statement.
"Many of the smaller and family-run businesses that have been impacted by Eva and Desmond will not have commercial insurance in place due to the impact of the recession and lower business volumes in recent years."
A government-backed scheme to make flood insurance affordable is due to launch in April. But the scheme, Flood Re, does not cover small businesses.
Consultancy KPMG has put the potential economic losses at more than 5 billion pounds, including 2 billion pounds for flood defenses.
($1 = 0.6749 pounds)
(Additional reporting by Padraic Halpin in Dublin; Editing by Dominic Evans)