When did Florida have its last tornado?

23.5.2011

A tornado razed the small town of Joplin in the US state of Missouri on Sunday. Over 100 people were killed, hundreds were injured, and many are still missing. The cyclone swept through the middle of the city, aerial photographs show a ten kilometer long and one kilometer wide swath of devastation.

The storm wreaked havoc in many areas of Missouri, but the worst hit was Joplin: three quarters of the city's 50,000 residents are in ruins. The tornado covered roofs and tore entire buildings to pieces. Houses, churches, supermarkets and gas stations were badly damaged or completely destroyed. A seven-story hospital was badly hit, and its medical equipment was thrown up to a hundred kilometers away. The clinic was evacuated because of the risk of collapse and the patients were taken to emergency shelters. The rescue measures are made even more difficult by the failure of the electricity and telephone network. Auxiliary workers report a tremendous amount of destruction. Three quarters of the city are practically completely wiped out.

The residents were warned too late about the storm: because the tornado was covered by rain and hail, its destructive power could not be predicted. Jay Nixon, governor of Missouri, has now declared the region a state of emergency. Warnings were issued against further storms in Missouri.

The tornado road

More than 1,000 tornadoes pass through the United States each year. 500 to 600 of the dreaded hurricanes alone take the route of the notorious "tornado alley". The "road of tornadoes" runs through the US states of Texas, Oklahoma, Kansas and Nebraska. There the conditions for tornadoes are particularly favorable: warm, humid air that rises over the Gulf of Mexico meets unhindered, dry, cold air from the north in the plains of the Great Plains. Violent thunderstorms arise here, from which many tornadoes develop. But not only the United States of America, Germany also counts some of the dreaded tornado every year. But because the Alps prevent warm, humid air from the Mediterranean from reaching us, tornadoes are much rarer here.

30.8.2005

It's one of the worst natural disasters in the United States. Hurricane Katrina hit the American Gulf Coast on Monday morning (August 29, 2005). At 280 kilometers per hour and accompanied by torrential rain, the tropical cyclone hit the coast and the city of New Orleans.

Katrina's gusts of wind simply swept people, cars and houses away. The US states of Florida, Alabama, Georgia, Mississippi and Louisiana suffered severe damage from the hurricane. Worst of all, however, is the city of New Orleans, with a population of just under 500,000. In the afternoon, the city's dams, some of which are below sea level, broke at 150 meters. The masses of water shot into the center and flooded a good 80 percent of the area. Entire residential areas are now completely under water. However, due to the power outages, the floods cannot be pumped out. An airport has also been flooded and had to be closed. Many access roads are closed - New Orleans is almost completely cut off from the outside world. The rescue measures are in full swing, but disaster control is completely overwhelmed. The city is sinking into brackish water and chaos. Looting and acts of violence have already been reported.

The warnings of the storm came too late for many. Only a million people were able to leave the New Orleans area in time. Thousands of people who could no longer escape are now stuck in the "Louisiana Superdome" football stadium and hope that the masses of water will drain away soon. It is not yet known how many people lost their lives to Katrina. Several billions in damage are expected.

Where did Katrina come from?

A tropical storm developed over the Bahamas on August 23, which meteorologists named "Katrina". The storm grew into a hurricane and hit the southern tip of Florida on August 25, killing nine people. Overland, Katrina weakened slightly. However, shortly after reaching the Gulf of Mexico, Katrina regained momentum and became a hurricane again. Katrina reached her maximum strength and hit the south coast of Louisiana on the morning of August 29 with wind speeds of 280 km / h. This made it one of the worst storms ever recorded in the Gulf of Mexico - with devastating consequences. Even meteorologists hadn't expected such a destructive force.

19.1.2007

With wind speeds of over 200 kilometers per hour, Kyrill raged in Europe on Friday night. Peak values ​​of the hurricane were measured on the Feldberg in the Black Forest and on the Brocken in the Harz Mountains. 47 people were killed in the hurricane and many were injured. The damage is estimated at billions.

It was the worst hurricane since Lothar: Kyrill uprooted trees, covered roofs and smashed cars. Several people were killed by falling trees and over a hundred were injured. The power grid collapsed in numerous regions. At Berlin Central Station, hurricane gusts tore a ton-heavy piece of iron from the facade. The station had to be evacuated, nobody was injured. Everywhere in Germany the fire brigade and police were in constant use, in many places there were disaster alarms.

The rail traffic had to be stopped at times. Overhead lines were broken, fallen trees blocked the tracks. Kyrill also completely mixed up air and shipping traffic. The hurricane hit the German North Sea coast less badly than expected, and the feared storm surge did not materialize. In contrast, the forest in North Rhine-Westphalia suffered severe devastation. Millions of trees have been knocked over or torn from the ground with their roots. Kyrill also left a swath of devastation in Great Britain, France and the Netherlands.

On Friday morning the authorities gave the all-clear, the storm and storm surge warnings were lifted. After the hurricane chaos, the clean-up work is now in full swing.

Storms of the century Kyrill and Lothar

The images are the same: shaved forests, bent electricity pylons, crushed cars. Hurricane Lothar swept across Central Europe in December 1999 even more violently than Kyrill. In northern France, Switzerland, southern Germany and Austria in particular, Lothar reached top speeds of 270 kilometers per hour and caused the worst storm damage: 110 people died; total damage amounting to more than 6 billion US dollars was caused. And now another storm of the century with Kyrill?

Climate researchers suspect that such violent winter storms will occur even more frequently in the future due to climate change. Because the storms that sweep over Europe in the winter months have their origin over the North Atlantic. The warming of the oceans now ensures that more water evaporates there. This in turn favors the formation of hurricane lows like Lothar and Kyrill.

Cyclones

In August 2005, the southeastern USA experienced a disaster: Hurricane Katrina raced over the coast, killing almost 2,000 people. Like all hurricanes, Katrina was a tropical cyclone. In other regions of the world they are also called typhoon or cyclone. Storm surges, torrential rains, landslides and floods are their consequences. But how does such a hurricane come about?

A hurricane occurs where warm water evaporates and moist, warm air rises quickly and high. Cold air is sucked down to compensate. A thunderstorm is approaching. As a result of the Coriolis force, the cold and warm air masses begin to turn as if in a spiral. By rotating, they suck in even more warm, moist sea air. The cyclone is getting stronger and stronger: it can reach a diameter of several hundred kilometers and cover thousands of kilometers. Its air masses can reach speeds of up to 300 kilometers per hour. Only in the center there is no wind: that is the eye of the hurricane. It can take over a week for the storm to subside.

In order to form such a cyclone, the water must have a temperature of at least 27 ° Celsius. In addition, the Coriolis force is required, which causes the air masses to rotate. In the direction of the poles the water is too cold, in the direction of the equator the Coriolis force is too low. For this reason, hurricanes only occur in a strip in the tropics, which is roughly between the 5th and 20th parallel.

Tornadoes, also known as “tornadoes”, are smaller, but much faster than hurricanes. They form in hot and humid regions when warm and cold air meet during a thunderstorm. Like a huge trunk, they descend from a thundercloud to the ground. Inside this trunk there is very little air pressure, which sucks in the air masses and whirls them around. Such tornadoes can be very small, but can also have a diameter of up to 1.5 kilometers and are clearly visible from a distance because they pull dust and water vapor far upwards. The ghost is over after a short time.

Where the tornado races along, however, it leaves a swath of devastation. The dangerous air eddies are particularly common in the American Midwest. There is even a real “tornado street” there: Because cold and warm air masses from north and south collide unhindered here, several hundred tornadoes race through this area every year.