Extreme Weather
January 18, 2007
Andreas Friedrich is a member of the German Weather Service's prediction department.
DW-WORLD.DE: The extreme low-pressure system "Kryill" will reach Germany's North Sea coast Thursday afternoon. What do you expect the consequences will be in the country?
Andreas Friedrich: We expect there will be winds that reach storm levels across the entire country, which is something that sets this low-pressure system apart. "Storm level" means wind strength 11, which is over 100 kilometer per hour (62 mph). They are expected across Germany this afternoon (Thursday), when the first storm warnings go into effect. In some areas, especially in the mountains, they will reach speeds much faster than hurricane strength.
Do you expect heavy precipitation?
Yes, that is the second element that stormy weather can take on. There will be heavy rainfall, especially in the low mountain ranges and the west, where as much as 40 liters per square meter (about 10 gallons per 10 square feet) could fall within 24 hours. That would be enough to cross the storm threshold so that people should expect floods in small and mid-sized river encatchment areas.
The German Weather Service has been under criticism for incorrect weather predictions since the 1999 storm "Lothar," which caused $6.4 billion worth of damage (5 billion euros) across Europe. Has the service become more careful about issuing warnings and how does that affect the current situation?
No, we have not changed our tactics or threshold levels. With this low-pressure system, we could give a very early warning. That is a result that was clearly forecast by weather prediction models a few days ago. There are other weather situations, particularly in the summer, when this is simply impossible. Then you cannot predict if a storm that appears to be local will spread and hit certain areas in the future or not.
Are weather phenomena like "Lothar" and other "storms of the century" a sign of climate change?
An individual event cannot be connected to climate change. In order to do that you need observations that span decades. But the climate models predict that if these trends are confirmed and the increase in temperature continues, winters will have heavier precipitation. This precipitation is connected to intense low-pressure situations. One could expect that these weather conditions will appear more often in the winter.
Is the "Kryill" low-pressure system nothing but hot air when compared to the hurricanes and typhoons that occur in other regions of the world?
Tropical cyclones naturally have stronger winds than this kind of non-tropical, low-pressure system. Hurricane winds can reach a speed of up to 300 kph. But what we are experiencing now is an unusual development that only occurs in central Europe every few years.
Christoph J. Heuer interviewed Andreas Friedrich (sms)