Due to its high w-ind speed, a storm causes major destruction to buildings and in nature.
When is it a storm?
Popularly, a strong wind is called a storm, but according to the KNMI standards it only storms at wind force 9.
Wind speeds from 20.8 to 24.4 m / s occur within a low-pressure area. In a heavy storm it blows at 24.5 to 28.4 m / s and a very heavy storm has speeds of 28.5 to 32.6 m / s. Above that, from wind force 12, we speak of a hurricane.
Due to its high w-ind speed, a storm causes major destruction to buildings and in nature.© SHUTTERSTOCK
How does a storm arise?
A storm starts as a failure in the zone that separates warm from cold air. The front is constantly moving, and warm air is pushed up while the pressure drops close to the surface. With that pressure drop there is more movement around the center of the low-pressure area, and ultimately a balance is created between the pressure forces of the low-pressure area and the coriolis force, which pulls all movement in our hemisphere to the right.
At the top of the troposphere there is a similar process whereby a low pressure zone is created in the cold air mass. As a result, the cold air draws harder to the warm, so that the process around the low-pressure area is strengthened. And as long as the process is not disrupted by other meteorological systems, it thus strengthens itself and extracts its energy from the imbalance between cold and warm air.
Autumn storms arise when a large low-pressure area from the Atlantic Ocean lands. The low pressure occurs with large temperature differences in the atmosphere. In the autumn, warm air from Southern Europe collides with cold polar air.
The warm air is pushed up and expands; therefore the pressure drops. The low pressure area draws in air and a wind is created that can easily get the power of a storm.
Storms occur especially in the fall when a strong low-pressure area from the Atlantic Ocean crosses Northern Europe and collides with warm air from Southern Europe.© SHUTTERSTOCK
The most powerful wind often occurs in the fierce rain, hail or thunderstorms of the cold front, or in the wake of the cold air. In extreme cases, where the wind speeds reach a hurricane force, the highest wind speeds are measured in the warm air just before the cold front, with an extra strong wind a few hundred kilometers away from the center of the low-pressure area.
What is the Beaufort scale?
The Beaufort scale is divided into 13 different wind forces. It is named after Francis Beaufort who established the scale in 1805.
The scale has been determined empirically. It was originally conceived from the effect that the wind had on the sails of the frigate of Beaufort, where 12 meant that all sails were full. Since then, others have added wind speeds to the Beaufort scale.
The wind force on the Beaufort scale indicates the force that the wind can have over land or at sea.
On the Beaufort scale, a storm has wind force 10. Wind force 10 means a wind speed of between 24.5-28.4 m / s, and a powerful storm with wind force 11 has a wind speed of 28.5-32.6 m / s s.
The Beaufort scale shows the influence of the wind on land and sea. During a storm enormous waves are created and the visibility is deteriorated by the spraying foam.
With wind force 10-11 on the Beaufort scale, a lot of damage is done on the mainland. On houses and trees for example. If you follow the scale, you will see on the water that there are huge waves and that the sea level is almost completely white due to the foam.
Name lists rotate between areas
For areas where there are many storms or hurricanes, the WMO (World Meteorological Organization) has drawn up an official, alphabetical list of alternating boy and girl names.
There are several lists that rotate between different areas. Each list is used again every six years, so that the names come back. If the storm has a particularly violent and destructive character, the name will not be used again and will be removed from the list.