Could the latest North Yorkshire floods have been prevented - or at least predicted? Probably not, finds STEPHEN LEWIS.

ANOTHER year, another flood. As the people of Helmsley - and other North Yorkshire communities - hit by Sunday's devastating flash floods begin the slow process of rebuilding, questions will inevitably be asked.

Could more warning have been given? Wasn't there anything that could have been learned from the great floods of 2000 that could have prevented this? And what can be done to make sure it doesn't happen again?

In this case, the answers to the first two of these questions really does appear to be no. Like Boscastle a year ago, Sunday's flash flood seems to have been a freakish event, an Act of God in the words of one Yorkshire councillor.

Weather forecasts on Saturday and Sunday had warned of the likelihood of thunderstorms and heavy rain across parts of North Yorkshire. The Met Office put out flash-flood warnings for the Pennine region at about 1pm on Sunday. But nobody could be more precise about where the storms were likely to hit. And nobody could have predicted the sheer intensity of the rainfall that lashed the western North York moors - or the devastating consequences it would have.

Normally, in the whole of June, we can expect an average of about 70mm of rainfall. On Sunday, at Hawnby up on the moors north of Helmsley, 70mm of rain fell in less than three hours - 60mm of that rain fell in a single hour.

With the ground baked hard by the hot weather of the previous few days, there was nowhere for the water to go. So it was funnelled down the Rye valley to Helmsley and other villages at the foot of the moors.

Chris Parkin, one of two councillors who represent Helmsley on Ryedale District Council, says nobody could have anticipated the ferocity of the flash flood - especially given the fact that Helmsley hadn't flooded for 70-odd years.

"How often do you have a 7 ton van picked up and carried across a car park?" he said. "There were weather warnings, and people in the area could perhaps have expected something. But nothing like this."

He is just thankful the floods did not hit 24 hours earlier. "We would have had 5,000 bikers floating around in Duncombe Park," he said. "It would have been a major, major crisis. They would have gone to sleep in their tents and woken up to be engulfed by water. I suspect we would have been finding bodies in the river. So in one way we were extremely lucky."

Francesca Glyn-Jones of the Environment Agency said the reasons for the flash flood were complex. It was partly the sheer intensity of the rainfall, and partly the fact the ground had been baked hard and was unable to absorb the water.

Local geographical factors also played a part: for example, the fact that much of the rainfall fell high up on the moors, and in such a short space of time.

Different areas flooded in different ways, she said: at Helmsley and Sutton-under-Whitestonecliffe the flash floods were a result of rivers or streams unable to cope with the volume of water bursting their banks. Nearer Thirsk, however, communities were flooded by surface water - local rainfall that had nowhere to go.

That highlights the fact that not all floods are the same. Hilary Saynor, who represents Stamford Bridge on East Riding of Yorkshire Council and who opened the town's £3.7 million new flood defences last autumn, says there was little that could have been done to prevent the flooding at Helmsley.

Providing flood defences for a town such as Stamford Bridge that was regularly inundated was one thing, she said. Preventing a freak flash flood of the kind that hit Helmsley - a town not normally subject to flooding - was quite another.

"It was a totally different situation to what we faced in Stamford Bridge," she said.

"I don't think there is anything that can be done about that sort of situation - short of us all stopping using cars and aeroplanes so as to address global warming. I feel desperately sorry for the people affected, but while there will be the odd person saying something ought to be done, I don't think anything can."

Gordon Clitheroe, chairman of the Pickering Flood Defence Group, believes there are things that can be learned from the latest floods. If more effort were put into ensuring rivers and watercourses were properly dredged and cleared of weed and vegetation, it may have helped to contain the water, he said. But he agrees no one could have predicted Sunday's inundation. "It was a surprise. It came from nowhere," he said.

So what of the future?

The Environment Agency is warning that flooding and other extreme weather events are going to be more common in the future as a result of climate change.

With towns subject to regular flooding such as Pickering still unprotected by flood defences, it is "far too early" to begin talking about defences for Helmsley - a town with, until Sunday, no history of flooding, an agency spokesperson said.

However, in an attempt to learn more about what causes flooding in the region - and improve measures to protect properties from flooding generally - it is appealing for people affected by Sunday's floods to come forward with eyewitness accounts.

Flood victims are being asked to fill in questionnaires and supply photographs to help the agency builds up as full a picture as possible.

"It is essential we get as much information as possible about flooding so we can improve our response to similar problems in the future," said the agency's area flood defence manager Peter Holmes. "The best people to give us eye-witness accounts are residents themselves.

"Thanks to climate change, we are going to see more extreme flooding and everyone needs to be prepared. Gathering the most up-to-date information is one of the best ways of anticipating future flooding."

The agency is also keen to have more say on the building of new homes in flood plains. At the moment, it can advise local planning committees on the risk of flooding but cannot veto applications. As a result, nationally last year 12 per cent of all new homes that the Environment Agency objected to on the grounds of potential flood risk were built anyway.

In Yorkshire - a region familiar with the devastating consequences of floods - that figure was much lower, at just one per cent. The agency still welcomes moves to strengthen its powers, however.

Later this year the Government will be consulting on a draft Planning Policy Statement 25, which would stipulate that applications for major developments in flood risk areas which local authorities want to push through against Environment Agency objections would be subject to calling in by the environment secretary for a decision.

That may be one way of reigning in the explosion of new homes being built in flood-risk areas.

Developments are also expected in the met office's ability to make more precise extreme weather warnings in the event of freak events such as that on Sunday

A new, more sensitive computer model is being trialled which would make possible more precise pin-pointing of where such extreme weather events would be likely to strike.

The system may be up and running by the end of the year - but even then, it would be unable to tell in advance more accurately than within about 10-12km exactly where a flash flood was likely to strike. "We've still got a way to go," a spokesman conceded.

Sunday is a stark reminder that, for all our apparent power to shape our environment, sometimes nature just cannot be controlled or anticipated.

Back to 2000...

The flash floods which struck Helmsley and other North Yorkshire communities with such devastating force on Sunday came in an instant.

This was different to the slow rising of the waters which caused such devastation in November 2000. Then, it was only after several days of unprecedented rainfall that the flood bells began to toll.

First, Pickering Beck overflowed and swamped properties and roads. Pickering was followed by Malton, Norton and Stamford Bridge and, soon after, York and then Selby.

As the waters rose, thousands of sandbags were distributed by emergency workers toiling around the clock. Police, fire and ambulance workers and the Army all helped evacuate stranded families.

For many communities, it was heartbreak all over again: Malton, Norton and Stamford Bridge had all been flooded the year before. In Naburn, residents once again found their village marooned and their properties inundated. Once the floodwaters had peaked, it was still days before water levels were back to normal.

The massive clean-up operation then took months. In Helmsley, it is just beginning.

If you would like to respond to the Environment Agency's appeal for eyewitness accounts of Sunday's floods contact the Agency on 01904 822537or a questionnaire and pre-paid envelope. All photographs will be returned.

Updated: 09:32 Tuesday, June 21, 2005