Severe thunderstorm warning: with reference to the May 9th Otter Valley Flood with Brian Golding
Cellar Bar Kennaway House EX10 8NG
The extreme rainfall in the Otter Valley on May 9th lasted over 3 hours and is estimated to have amounted to a little over 100mm of rain, an amount with about a 0.1% probability of occurring per year. Somewhat more rain fell in South Somerset on the same day. This was not enough rain to raise the River Otter very much, and only caused minor flooding of the River Sid. On the other hand, it produced torrents of water along tracks and ditches running off Aylesbeare Common into Newton Poppleford and Tipton St John, sufficient to flood houses, block roads and demolish a wall. I will show that several thunderstorms were involved, each of which contributed to the impact, but it was the last one that did most of the damage, the rain falling on already sodden ground.