Recent heavy rain over western UK

18 November 2010

Heavy rainfall across Cornwall and parts of Wales on the night of 16/17 November 2010

Analysis chart - valid 0000 UTC Wed 17 Nov 2010

Background

An occluded front associated with a deep Atlantic depression, slowly moved in from the west during the night of 16/17 November 2010 to bring heavy rain across parts of Wales and south-west England. The rain was particularly heavy across Cornwall, where torrential downpours occurred at times — overwhelming drainage systems and bringing a rapid rise in river levels.

Impacts

At one stage there were 25 flood warnings in force across south-west England. Some of the worst hit areas were St Blazey, St Austell, Mevagissey and Lostwithiel. A combination of rivers bursting their banks and drains not being able to cope with the intense rainfall, resulted in torrents of water flowing through the streets. Some motorists were trapped in their cars as the flood waters rose to two metres in places. Search and Rescue helicopters were scrambled to assist in the rescue efforts. More than 100 homes were evacuated but Devon & Cornwall Police have said there were no reports of serious injuries. Landslides also added to the chaos severely disrupting train services in south-west England. In parts of Pembrokeshire, Carmarthenshire and Swansea there were also reports of flooding on many roads with some properties affected. Mid and West Wales Fire Service and Dyfed Powys Police attended an incident at Llangwn near Neyland where motorists had become stranded in flood water.

Weather data

Rainfall data from the Met Office indicated that the wettest place in Cornwall was Cardinham, where 50.2 mm was recorded between the hours of 2200 on the 16th and 0700 on the 17th. The hourly rainfall data is reproduced below showing particularly intensive rainfall in the hour up to 0600 when over 18 mm of rain fell. Rainfall data from other gauges in the area does not indicate such intense rainfall.

Cardinham hourly rainfall from 2200Z on 16th to 0900Z on 17 November 2010

How we did

The joint Met Office/Environment Agency Flood Forecasting Centre issued an extreme rainfall alert during the afternoon of 16 November, to give emergency responders and local authorities advance warning of the heavy rain. Severe weather warnings were issued during the evening of the 16th for Cornwall, Devon and southern parts of Wales. National and local weather forecasts on TV and radio highlighted the 'torrential rain and gale force winds' in south-west England and Wales through the day on the 16th.

Please note that all values and statements are provisional and subject to change.

Contact information

Met Office Press Office: +44 (0)1392 886655

E-mail: Press Office

Met Office Customer Centre: 0870 900 0100

If you're outside the UK: +44 1392 885680

Last updated: 21 April 2011