Extratropical Cyclone Xaver last week caused power and communications disruptions that affected 500,000 households throughout northern Europe, according to catastrophe modeling firm AIR Worldwide. The storm also caused widespread travel disruptions, shutting down ferry and rail service and grounding flights.

Xaver affected large parts of northern Europe, particularly the United Kingdom, Northern Ireland, Germany, the Netherlands, Belgium, Denmark, southern Sweden, Poland and the Czech Republic.

The storm followed approximately five weeks after Windstorm Christian battered Denmark, Germany, the Netherlands, France, the U.K. and Sweden in late October. AIR estimated insured losses for Christian of between EUR 1.5 billion and EUR 2.3 billion.

“Hurricane-force winds caused widespread power outages and travel disruptions throughout the region, but the greatest threat from Xaver resulted from its massive surge,” said Dr. Nicolai Thum, senior research associate at AIR Worldwide. “Storm surge in the United Kingdom and the Netherlands was the highest seen since the deadly North Sea floods of 1953. However, flood defenses in both countries have been significantly strengthened since then, which helped to limit damage. Storm surge was also significant near Hamburg, which saw significant flooding in 1962 from a similar storm, but coastal defenses around the German city held and damage was limited.”

The U.K.’s Environment Agency reported that 1,400 properties were damaged by flooding in coastal communities in Yorkshire, Lincolnshire and northeastern Wales and by heavy precipitation that caused rivers to burst their banks. According to the EA, more than 2,800 km of flood defenses successfully protected more than 800,000 properties from some of the highest storm surges since 1953. The Thames Barrier was closed twice during the storm, successfully protecting London from flooding.

“In Germany, six-meter high waves battered Hamburg—the second highest surge level since 1825, the first year for which recorded measurements are available,” Dr. Thum noted. “Tidal floods that hit Hamburg were similar to those that drenched the city in 1962, causing the worst flooding in living memory. Hamburg’s harbor area and historic ‘Fischmarkt’ were submerged by Xaver’s storm surge. However, improved coastal defenses along the North Sea limited Xaver’s impact.”

In the Netherlands, the Eastern Scheldt barrier was closed for the first time in six years on Dec. 6, just ahead of the high tide. Water levels reached up to four meters—again the highest since 1953—but the flood defenses protected low-lying regions in the Netherland’s southwest delta.

In Denmark the towns of Frederikssund and Frederiksvaerk, northeast of Copenhagen, were evacuated by police.

“Based on initial assessments, Xaver’s wind impact is expected to be less than that of Christian, as wind speeds were generally lower in regions affected by both storms. Winds toppled trees and caused widespread roof damage throughout the affected region, but significant structural damage is expected to be limited,” Dr. Thum concluded.

Source: AIR Worldwide