Answer:
Causes of the Flood
Physical Causes
The flood took Boscastle entirely by surprise - it was a flash flood event & the village is
not prone to regular annual flooding as many locations affected by extreme flooding
events are. In fact, the village had never experienced such a flood, suggesting that the
flood was the result of a combination of exceptional factors.
A major factor is the location of the village, within the Valency valley. The Valency is
normally a quiet stream, which follows a very steep course down into the valley from the
hills around. The valley's structure is likely one of the most major physical factors, as its
steepness accelerated the rainwater falling on the hills above the valley greatly as it
travelled down to the valley floor where Boscastle stands. As well as causing the water to
travel extremely quickly down the valley sides, the shape of the valley concentrated
rainwater from the surrounding area into a relatively narrow space descending towards the
valley bottom. Not only did this cause an increase in run-off speed, but also an increase in
discharge volume, which was later to prove devastating in the confined river channel
flowing through the village itself, which simply couldn't hold enough water to prevent the
flooding which occurred.
The next major factor was the weather that day - arguably the most major factor. The
entire South-West of the country had been battered with stormy weather over the days
leading up to the flood on the 16th of August, and as a result the ground was saturated.
The 16th was a very hot day, with clear skies in the morning & high temperatures for much
of the day. The combination of high localised temperatures & the abundance of
unabsorbed surface water, coupled with moist winds off the sea & the effects of the local
relief (Bodmin Moor) caused a great deal of moist, warm air to travel upwards quickly.
"A line of thunderclouds rocketed over 10km high, their tops streaming into anvil shapes
as high-level winds swept air away from the storm, helping suck more air from below."
The formation of storm clouds was rapid
& soon Boscastle was overshadowed by
a menacing storm cloud. By early
afternoon, the rain had started, and
within a few hours a massive 5 inches of
rain had fallen in Boscastle alone. When
the flow in the valley was met by the
water funnelled down from the moors
through the steep valley (unhindered by
soil absorption due to the saturation of
the land), the sheer volume of water in
such a small space at once caused the
Valency to burst its banks & cause the
exceptional level of damage in the
village.
The person who write this before is SUCH A CHEAT! i read this on another website. I hat this question and PLEASE NEVER RECCOMEND THIS TO ANYONE ELSO. WIKI ANSWERS IS crap!