Winds and torrential rain left one person dead and forced hundreds from their homes - as David Cameron promised the Government would "ensure everything is being done to help".
The Prime Minister's comments came as the Environment Agency revealed more than 800 homes have been flooded, with thousands of motorists rescued from water-logged roads.
A woman was killed when she was crushed by a tree as wild winds whipped southern England, bringing the week's weather-related death toll to two.
And forecasters have warned worse may still be to come, with further rainfall and 60mph winds expected overnight, and experts warning people the conditions pose a "serious threat to life".
Rainfall is estimated to be around 15mm across the spine of Britain on Monday, less than the 30mm of rain in pockets of the West Country, but meteorologists said it would offer little respite to weary homeowners keen to begin the clean-up.
Mr Cameron wrote on Twitter: "Shocking scenes of flooding in Cornwall and around the country. Govt will help ensure everything is being done to help."
Although Sunday afternoon saw a temporary respite, the Environment Agency has continued to issue warnings, with over 500 alerts now in place. One severe flood warning - the highest alert possible - remains in place for the River Cober in Helston, Cornwall. At one point this weekend, four were in place.
More than 500 alerts have now been issued, including nearly 230 flood warnings - the second strongest alert - and confined largely to the Midlands as bands of rain which brought sorrow and destruction to the South West moved northwards.
A 21-year-old woman became the second victim to die as a result of this week's weather after she was killed in Western Way, Exeter after becoming trapped under a fallen spruce tree which injured two others. It follows the death of a man on Thursday, who died when his car became wedged under a bridge near a ford in Rectory Fields, Chew Stoke, Somerset.
Environment Minister Richard Benyon met with people in Malmesbury where three feet (90cm) of water was reported in some parts of the Wiltshire town. He described the clear-up work as "heroic", adding: "While many houses have been flooded, some haven't because of the efforts of these people. The Government's job, first of all is to make sure people are as prepared as possible with a changing climate ... for these extremes of weather. Secondly, we've got to continue building flood defences."