Many Bradford residents will have experienced an uncomfortable weekend thanks to the ferocious storm which swept over the district.

And experts have blamed a well-known phenomena caused by winds being funnelled down from the Pennines as warmish south westerly winds whipped through the Aire Valley.

In Keighley six residents - including 65-year-old Harry Palmer - had to be evacuated from their homes as a 100ft tree came toppling down, and several roads including the A65 were affected by falling trees.

There was no official measure of wind speed in the Bradford area but in Leeds it was measured at over 70mph.

Bradford's proximity to the Pennines means it is susceptible to strong winds according to Dr Darren Comber, lecturer in environmental science at Bradford University.

He said: "The Pennines are a fairly upstanding ridge of land and the wind hit Bradford at maximum speed channelling wind into the Aire Valley.

"There's a tendency for air speeds to increase more up here, the topography exacerbates the general condition. The wind comes across out of the south west and races uphill. It's a fairly steep slope towards the west that causes it to accelerate.

"Compress more air into a space vertically and the wind picks up. It's a well-known feature of the mountain tops. We could tell it was going to be a windy weekend."

Michael Dukes, London-based senior forecaster for the Press Association, and originally from Ilkley, said: "It can come out of the blue but it only happens in certain conditions where there's usually a brisk south westerly wind following a quite mild tropical maritime wind."

He said the air becomes more turbulent as the compressed air is squeezed over the Pennines producing stronger winds.

And, he recalled, one of the worst occasions occurred on the eastern side of the Pennines in when Sheffield was hit badly on February 16, 1962.

Winds oF 90mph, left a trail of destruction in their wake. Three people were killed, 250 injured and seven thousand houses were damaged.

He added: "It's the exaggerated wave motion that's to blame - it's the turbulent nature of it, not necessarily the speed."

Converted for the new archive on 30 June 2000. Some images and formatting may have been lost in the conversion.