BRITAIN: A combination of coastal winds, unstable air and heavy rain led to flash floods which ripped through the Cornish village of Boscastle, according to experts.
Localised weather conditions caused an estimated metre of water to pour through the village, trapping residents, washing away cars and sparking a major rescue operation.
Mr Wayne Elliot, a Met Office forecaster and spokesman, said: "This weather pattern formed locally. The air was unstable, which allowed for bad weather, and then there was a trigger mechanism in one location."
This unstable air was created by two air masses, one inland and one offshore. When they converged, it triggered the air to rise, cooling and creating rain. In addition, coastal winds were converging, giving some extra "oomph" to the weather, Mr Elliott said.
"We can't forecast exactly where these weather conditions are going to be, but we do know the area is at risk. There have been a lot of big flooding events in the south-west in which unbelievable amounts of rain can fall."
The location of Boscastle makes it vulnerable to incidents such as Monday's. Fishing villages are often situated at the end of rivers which make them prone to flooding.
In this case, the village stands in a deep coomb or hollow where two valleys meet, formed by the rivers Valency and Jordan. A third river, Paradise, also flows through the village.
Inland, the high ground of the moorland acts as a trigger for the weather, forcing the air to rise and cool, creating rain.
"Ex-hurricane air" has been moving into the north Atlantic and will bring more heavy rain and winds to Britain throughout the week, although not on the scale of last week's deluge.
As residents in the village tried to come to terms with the damage wrought by the rampaging water, scientists offered differing opinions as to what had caused the torrential downpours.
Dr David Viner, a senior scientist at the Climatic Research Unit at the University of East Anglia, was one of those who felt the floods could be attributed, at least in part, to climate change.
He warned that changing rainfall patterns meant rapid, unpredictable and flash floods would become more frequent.