RMS Comments on Windstorm Johanna

The strong winds and heavy rain impacting the UK and France are a result of a deep low pressure system crossing the UK called windstorm Johanna. There are reports of power outages, downed trees and scattered damage in southern England.

As Johanna continues to track east across the UK, winds are expected to ease in the south of England for a time and then increase again. The Met Office has warnings in place for Severe Gales in South West England, with gusts reaching up to 120-140km per hour in parts of Cornwall and the Isles of Scilly.

The storm has coincided with spring tides in the south of England, and strong south to south-westerly winds over the Atlantic and in the Channel have built up large swells and high seas. The Environment Agency (EA) started issuing flood warnings on Sunday, 9 March and as of Monday morning, 10 March there were 7 severe flood warnings in place covering Cornwall and Devon and 58 flood warnings, mainly focused in the South of England. Particularly heavy bands of showers associated with the storm, moving east across southern areas of England could exacerbate the situation in the next 6-12 hours.

Meteo France has wind warnings in place for the northwest areas – for nearly 40 CRESTA areas. Possible consequences are power outages, trees downed, telephone line loss, roof and chimney damage, vehicle damage and road network interruptions. The agency has recorded gusts up to 130 km/hr on the northwest coast, but they are warning of further strong gusts and thunderstorms later today and tonight where winds could reach up to 130 km/hr on the coast and up to 100 km/hr inland.

Windstorm Johanna, which formed in the North Atlantic, is moving at a relatively slow speed and is a fairly large area of low pressure, unlike windstorm Kyrill which struck the UK in January 2007, moving east at a very high speed.

RMS is monitoring the situation and will continue to update its analysis of the damage and disruption caused by the windstorm.

Source: Risk Management Solutions, www.rms.com.