AIR Worldwide Reports on Winter Storm Xaver

According to catastrophe modeling firm AIR Worldwide, following less than six weeks after Winter Storm Christian, Winter Storm Xaver hit north of Scotland during the overnight hours. Wind gusts of more than 140 mph (225 km/h) were recorded in the Scottish Highlands, and across the northern UK there have been gusts of between 60 and 80 mph (96 and 128 km/h), with 100 mph (160 km/h) gusts recorded in mountain areas. The strongest winds are expected to decrease in strength later today; however, the risk of coastal flooding is expected to increase in the UK, the Netherlands, northern Germany, and Denmark.

An amber wind alert had been issued for northern and central Great Britain, including north and west Scotland, and yellow warnings for much of Great Britain, including London, Northern Ireland, and Wales. The UK’s Environment Agency has issued more than 200 flood alerts across England and Wales. Homes in Yarmouth, England, on the Norfolk coast have been evacuated in anticipation of storm surge, and Glasgow’s central rail station was evacuated after wind-borne debris caused a partial collapse of its glass roof.

Germany, the Netherlands, and Denmark are preparing for Xaver’s arrival. An extreme weather warning has been issued for Germany’s northern states, including Hamburg, Schleswig-Holstein, Lower Saxony, and Bremen. People in northern Germany have been advised to stay indoors. Red warnings, the highest level of weather alerts, have been issued for much of the coastline of the Netherlands. The entire country of Denmark is under orange alert, meaning potential dangerous and unusual weather expected. Weather warnings for southern Sweden are also in force.

“On Wednesday, December 3, a strong surface low developed in the North Atlantic, in an area called the Cold Conveyor Belt,” said Dr. Gerhard Zuba, senior principal scientist, AIR Worldwide. “This extratropical low pressure system strengthened due to a jet stream-induced upper level divergence. As it approached north of Scotland during the overnight hours, Xaver’s central pressure plummeted to 980 mb. A line of severe thunderstorms has developed along a cold front that is traveling across northern Europe today. Risk of tornadoes is possible.”

“Xaver is expected to gain strength today and reach its lowest core pressure of about 960 mb late Thursday afternoon local time over Denmark, where gusts in excess of 140 km/h (97 mph) have already been reported.”

All train service in Scotland was suspended by ScotRail due to equipment damage and debris on the tracks, and up to 100,000 homes in Scotland and about 6,500 in Northern Ireland are without power. The Thames Barrier will be closed this evening local time.

According to AIR, the flood gates protecting Rotterdam have closed for the first time since they were built, in the 1990s, and the Oosterscheldekering in southwest Netherlands is closed for the first time since 2007. Train services in Denmark have been suspended, and several bridges across the country have been closed.

According to the UK’s Environment Agency, storm surge could reach as high as it did during the 1953 North Sea floods, however new flood defenses should reduce the impact. The agency also expects about 3,000 properties to be flooded in the next 24 hours. Flooding has already been reported in north Wales, Northern Ireland, and the west coast of the UK.

Dr. Zuba noted, “Xaver is currently approaching the German coastlines and is expected to bring high winds and coastal flooding. Hamburg is expecting up to three spring tides to occur during Xaver over the next 36 hours, which is moving very slowly. With the actual spring tide expected to be higher than usual already, storm surges of between 1.5 and 2 meters (5 and 6.5 feet) are expected in Hamburg tonight, local time, and between 3 and 3.5 meters (about 10 and 11.5 feet) tomorrow.”

Source: AIR Worldwide