Extreme hurricanes in Norway are far from as powerful as the tropical hurricanes in the Atlantic. TV meteorologist,Kristian Gislefoss, explained why.
The most powerful hurricane we’ve experienced in Norway was on New Year’s Eve in 1992. Comparing wind speed with tropical hurricanes, that would correspond to a category 3 hurricane. Dagmar was a category 2, and Irma and
Maria, which recently ravaged the Caribbean and the Florida coast, were category 5.
Hot seas are the foundation of tropical hurricanes
In order for tropical hurricanes to form, it must be at least 26.5 degrees in the water down to 50 meters deep.
There must be heavy moisture in the lower part of the atmosphere, and cold air in the upper atmosphere.
Additionally, there’s a big change in wind speed over short distances. Tropical hurricanes are therefore formed on latitudes of between 5 and 30 degrees.
The sea in Norway is too cold
The sea outside Norway does not have the necessary high temperatures and low humidity in the lower part of the atmosphere. The low pressure received by Norway is formed at the polar front. There’s a distinction between cold air from the north, and hot air from the south, between 30 and 70 degrees north.
In recent weeks, powerful tropical hurricanes have swept across the American continent, creating total destruction. Here in Norway, we experience extreme weather from time to time, but hardly ever as powerful as the strongest tropical hurricanes.
Residues of hurricanes may reach Norway
A tropical hurricane won’t hit Norway, but the remnants of a hurricane can hit us. These are formed outside of Africa, and with the help of Eastern winds, they are transported westward to the American continent.
Along the way, low pressure can transform them into a tropical hurricane. Some of the hurricanes enter the country and die quickly, while others follow the eastern coast of the United States northward. Here the hurricane gradually weakens because the access to hot and humid air decreases.
Eventually, what remains of the hurricane hits the west-wind belt and is carried across the Atlantic Ocean to northern Europe.
The hurricanes have thrived on water vapour, but in order to survive in the west wind belt they depend on the temperature difference supplied by colder air from the north than they had in the south. In this way, they receive new energy.
Without it, they quickly die. The vestige of a hurricane can reach Norway in approximately 10 to 15 days, and may, from time to time, cause extreme weather here.
Source: yr.no / Norway Today