There are many (thunder) showers over the Netherlands, which can cause violent waterspouts. “And then you don’t want to float with your boat or your air mattress on the water,” says Marjon de Hond. from Buienradar.
It is especially true for the IJsselmeer. The warning issued by KNMI, lasts until 4 pm, but De Hond expects that it will be extended. Thunderstorms have also been predicted in Zeeland, South and North Holland and above the Wadden Sea, with the risk of whirlwinds.
Swirls
Whirlwinds can cause damage at high speeds, De Hond knows. They arise when there are large differences in wind direction and temperature at different heights. So-called vortices then arise – and together they can form a whirlwind. “Think of it as a funnel-shaped trunk that spins very quickly.”
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On the water, such a whirlwind is called a whirlwind. This is caused by a large difference between the water temperature and the temperature of the air above it. De Hond: “The water has heated up considerably in recent weeks, both in the sea and above, for example, the IJsselmeer. And the air above it is colder again, especially in such a shower.”
Don’t go sailing now
So no: De Hond hopes that not many people are on the water. “You just shouldn’t go sailing now. People should be warned about that, for such phenomena. A waterspout will only decrease in strength when it comes ashore or disappears spontaneously.”
Incidentally, you see them coming: they often originate further from the coast, and not close to the beach.
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There is also a lot of rain today and there is a chance of waterlogging. “The showers off the coast already looked violent earlier today. There is a lot of rainfall,” says De Hond. For example, 44 millimeters have already fallen in Hoek van Holland.
“That is a lot, it is going fast.” It is because the showers move very slowly, so there is relatively much water in one place.
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Also a lot of rain in Europe
Heavy rainfall is also expected in southern Germany next night, as well as northern Italy and the Alps. In some places there is more than 100 millimeters. Up to 80 millimeters can fall in just twelve hours. For comparison: that is more than we have in a month of July.
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As the showers and whirlwinds continue to travel into the country, they will gradually decrease in activity. In the evening it gets quieter, and tomorrow peace has returned for a very large part, De Hond assures.
“There will be some cumulus clouds, but certainly also sun. And only a shower in the northeast. It will certainly not be as intense as today.”
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