Storm Dennis promises 70mph winds and further heavy rain.
"Because the rain came though so strongly and the river rose so quickly, we physically wouldn't have had time to put the barriers up".
A yellow warning for wind covers Shropshire from 10am on Saturday until midnight on Sunday, as well as a yellow warning for rain. Coastal flooding will also be an issue, s Storm Dennis generates huge swells, particularly around western and southwestern coasts during high tides.
Storm Dennis Becomes A Menace Over The Weekend - Bringing Flooding & Gales - Blog by Nick Finnis
Forecasters predict "very heavy rain" will strike areas around the Brecon Beacons in South Wales, the Yorkshire Dales and Dartmoor in Devon from 3pm on Saturday to 3pm on Sunday.
"The strongest winds are likely to be on Saturday afternoon and evening, with a lull overnight, before increasing again during Sunday".
These include amber warnings stating that flooding could cause a danger to life, power cuts are expected and there is a good chance transport links will be impacted.More news: Today’s chat: Will you read or buy Colin Kaepernick’s new memoir?
Dennis started as a low forming over central / eastern US late on Wednesday, the low carried east by a strong jet stream off the New England coast last night and now moving under the "developmental" left exit of a 220 mph+ jet streak over the NW Atlantic, where it will deepen rapidly as it is pushed by the jet stream across the Atlantic, then takes a left turn towards Iceland by Saturday as it is pulled around a deep upper trough / vortex centred close to southern Greenland.
Met Office says 20-40mm will fall widely, with 50-80mm across parts of northern and southern England.
Storm Inès will arrive on Thursday, followed by Storm Dennis over the weekend.More news: 'Parasite' shares rocket after Oscar wins
River levels are likely to rise over the weekend and into early next week.
As of 11:30 am on 14 February there are 12 flood warnings, meaning that flooding is expected, and 98 flood alerts, meaning that flooding is possible, in place across the country. It said preparations were under way to operate flood defences, including the Foss Barrier in York.
The Environment Agency said there is a "heightened risk of flooding" across much of southern, central and northern England this weekend. It is important for people to be aware of their flood risk and stay safe by signing up for flood warnings, making a flood plan and remembering not to drive or walk through flood water - it's not worth the risk.More news: Beijing names Xi ally to oversee Hong Kong
Mr Box said the start of half term for some children this weekend means families should plan ahead or consider delaying their travels.