A MASSIVE rescue operation was launched after freak thunderstorms wreaked havoc across swathes of North and East Yorkshire.

Flash floods devastated communities in the Helmsley and Thirsk area, and more than 17,000 properties suffered power cuts.

RAF Sea King helicopters were called in to winch stranded people to safety and later scoured the countryside with heat-seeking equipment and spotlights for other storm victims.

Fire chiefs said that ten people were rescued from life-threatening situations in the Helmsley area by helicopters and firefighters, and another 33 people rescued from "non-threatening" situations.

Roads and bridges were blocked by flooding and landslides, a bridge at Hawnby, near Helmsley, was swept away, scores of homes were inundated and hundreds of farm animals feared drowned.

An elderly woman suffered a heart attack and was taken to hospital after six homes were inundated at Hawnby, north of Helmsley, and the village was cut off.

Homes were also seriously flooded at Sutton-under-Whitestonecliffe near Thirsk, where residents said sheds and trees were seen floating down the river in dramatic scenes reminiscent of the floods at Boscastle, in Cornwall, last year.

Weather experts said today that a whopping 40ml (1.6 inches) of rain had fallen between 1pm and 7pm yesterday - nearly the rainfall average for the whole of June. No more heavy rain was forecast today.

Some of the most serious disruption to motorists happened at Helmsley, where the main bridge over the River Rye was at one point completely submerged under floodwater. Engineers were today checking whether the bridge has suffered structural damage and is safe to re-open.

The B1257 between Chop Gate and Helmsley was closed after the floodwaters washed part of the road away, and the A19 north of Thirsk was closed by floodwater in both directions but re-opened early today. Inspector John Richardson, of North Yorkshire Police, said more than 50 officers, at least 20 members of Cleveland Mountain Rescue, paramedics and firefighters were involved in the operation.

He said: "We are quite used to suffering from flash flooding in this area, but nothing like this."

A spokesman for electricity suppliers NEDL today said a little under 5,000 homes in East Yorkshire and 1,400 in North Yorkshire were still to be restored to power.

He said the cuts, caused by lightning striking an electrical substation in Beverley directly, affected properties in a large number of communities, including Helmsley, Wilberfoss, Malton, Thirsk, Kilburn, Bridlington, Market Weighton, Bishop Wilton, Beverley and Driffield. TV reception in thousands of homes was knocked out after the storm affected the Bilsdale transmitter.

Updated: 10:24 Monday, June 20, 2005