Over 60mm of rainfall in less than 2 hours, typically their month's worth of rainfall.
The ground was already saturated due to the previous two weeks of which they had already had above their average monthly rainfall.
The drainage basin has many steep slopes, and has areas of impermeable slate causing rapid
surface run-off.
Cornwall
2004
UK
River Valency
Effects
Many buildings were swept away
Houses, cars and
businesses were all
swept away that
belonged to over 1000
people
Income from tourism was lost.
No lives were lost, partly due to the
rapid response of the emergency
services.
Causes
The flooding coincided with a high tide, making the impact
worse.
Boscastle is at the confluence (where
tributaries meet) of three rivers - Valency,
Jordan, and Paradise. A large quantity of water
all arrived within a short space of time causing
the rivers to overflow.
Responses
Major incident declared at 5pm.
RAF search and rescue were alerted to rescue trapped people.