Mighty North Sea Storm Xaver Battering Denmark, Germany, and the Netherlands

For the first time since 2007, the massive flood gates that protect the Netherlands from the North Sea have been closed, as a mighty North Sea storm hurls a huge storm surge propelled by near-hurricane force winds against the coast of the Netherlands, Germany, and Denmark. Windstorm "Xaver", as it is called by the Free University of Berlin, has already killed one person in Scotland, where a truck driver was killed and four people were injured in an accident west of Edinburgh when high winds toppled a vehicle onto several cars. Winds gusted up to 142 mph overnight in the Scottish Highlands; many roads and bridges were closed, and all train services in Scotland were suspended; Network Rail spokesman Nick King said that "there's too much debris and too much damage to equipment to continue." At 2:55 pm local time Thursday, oil rig F3 in the North Sea about 200 km (125 miles) north of the Netherlands recorded sustained winds of 83 mph, gusting to 99 mph. These winds were recorded at an elevation of 49 meters (161 feet), so were stronger than the standard winds measured at 10 meters at most world airports. Oil rig Ula off the coast of southern Norway recorded sustained winds of 91 mph, gusting to 108 mph, at 2 pm local time. On the west coast of Denmark at St. Peter Ording Airfield, sustained winds of 58 mph were recorded at 2 pm local time. Winds at Sylt, Germany were 58 mph at 5 pm local time (see the Sylt, Germany beach webcam here.


Figure 1. Waves lash the North Sea coast at the ferry dock in Dagebuell, Germany, on December 5, 2013. (CARSTEN REHDER/AFP/Getty Images)


Figure 2. MODIS satellite image of Windstorm Xaver taken at approximately 11 UTC Thursday December 5, 2013. Image credit: NASA Worldview.

Heavy wind damage likely
A squall line with severe thunderstorms has developed along a cold front that is sweeping across Northern Europe this Thursday afternoon, and these thunderstorms are bringing intense lightning, heavy rains, and damaging winds. The European Storm Forecast Experiment is warning of the risk of tornadoes with this squall line, and damaging wind gusts of up to 90 mph (145 kph) in the severe thunderstorms. The Thursday morning 00Z run of the European model predicted that Xaver would bottom out with a central pressure near 960 mb Friday morning; the GFS model had it stronger, at 956 mb. This will make Xaver stronger the October's Windstorm "Christian" (AKA the St. Jude storm), which bottomed out at 968 mb. Christian killed 18, and did $1.4 billion in damage. It is possible that the wind damage from Xaver will approach that of Windstorm Anatol, which hit Denmark, Southwest Sweden, and Northern Germany on December 3, 1999. Anatol had sustained winds of up to 91 mph (146 kph), killed 20 people, and injured over 800. Damage was $2.6 billion (1999 dollars) in Denmark, making it the costliest disaster in Danish history.


Figure 3. Severe weather warnings for Xaver from the European Storm Forecast Experiment.

3.5-meter storm surge predicted for Germany
The maximum storm tide of Xaver will be in Germany and Denmark, and will be unusually high, since we are only two days past the new moon. Fortunately, the German coast is well protected by dikes, which are about 8 meters high, and these dikes should be able to withstand Xaver's storm surge. The German weather service storm surge forecast made Thursday morning called for a storm tide of 3.5 meters (11.5') above average high tide in Cuxhaven and Bremerhaven during the high tide cycle early Friday morning. This is about 4.8 meters above mean sea level in Bremerhaven, which will be very close to the all-time record of 5.18 m above mean sea level set there in January 1976.

German storm surge history
The deadliest flood of the last hundred years in Germany was the "North Sea flood" in 1962 (16/17 February), where many dikes broke and 340 people were killed. In the Bremerhaven area, the dikes from the 1840s were just able to withstand the storm surge but were heavily damaged. Bremerhaven had installed storm surge gates at the mouth of the river Geeste in summer 1961 as a reaction to the 1953 flood in the Netherlands. That small-scale Deltaworks saved the city. After this catastrophe, the dikes along the German coast were strengthened. Just in time, as the highest storm surge of at least the last hundred years occurred in January 1976. In Hamburg, the 1976 flood was 4.35 meters (14.3') above average high tide, which is 6.45 meters (21.2') above mean sea level. This is 75 cm higher than the storm surge of 1962, but the dikes were strong and high enough in 1976 to withstand the flood. Thanks go to Dr. Michael Theusner of the German climate museum Klimahaus for these stats.

Links
Weather graphics and storm impacts from Storm #Xaver from Tim Ballisty @IrishEagle
Sylt, Germany webcam
‪Dagebüll‬, Germany ferry terminal webcam
Thyboroen, Denmark webcam (thanks go to wunderground member barbamz for this link.)
24-hour storm surge forecasts and actual water levels for the North Sea coast
Tide chart for Bremerhaven, Germany. The highest storm tide will occur at high tide at 1:59 UTC (2:59 CET) on Friday morning.
German weather forum
Wikipedia's list of great European windstorms.
A list of the severest storm surges at the North Sea (in German) and a not so-detailed list in English here
The Future of Intense Winter Storms, my 2010 blog post on climate change and winter storms (updated in early 2013.)

Jeff Masters