Dozens of tornadoes rage across the U.S. - At least 33 dead

According to media reports, the storms and tornadoes killed at least 33 people, twelve of them in the state of Missouri alone. Dozens were also injured. In addition, houses and cars were destroyed, trees were uprooted and forest fires were fanned by the strong winds.

The National Weather Service warned of further storms that are expected to reach the east coast today. The US states of Alabama and Georgia are particularly at risk. In Georgia, Governor Brian Kemp declared a state of emergency and urged residents to prepare. Residents of high-risk areas should seek out buildings with underground shelters and avoid mobile homes. Millions of Americans are on alert.

Pile-up with 50 vehicles

Dust storms caused pile-ups involving dozens of vehicles. In a series of accidents in the state of Kansas, 50 vehicles crashed into each other, killing at least eight people. There were further fatalities in Arkansas (3), Mississippi (6), Texas (3) and Oklahoma (1). Hundreds of thousands of households lost power.

Hundreds of fires in Oklahoma

According to the Governor of Arkansas, Sarah Huckabee Sanders, it is likely to take months to clean up the enormous damage in her state. A police spokeswoman in Texas said: "We've had severe storms in the past, but not of this magnitude. It was terrible."

In Oklahoma alone, hundreds of fires reportedly broke out. They affected 170,000 hectares, an area twice the size of Hamburg.

More than 40 tornadoes

The storms began on Friday. In eight states - Missouri, Arkansas, Mississippi, Louisiana, Illinois, Tennessee, Alabama and Indiana - a total of more than 40 tornadoes were recorded. By way of comparison, according to the German Weather Service, there are an average of around 45 tornadoes per year in Germany.

Tornadoes occur when there are large temperature differences and often occur together with thunderstorms. A trunk-like tube of cloud extends from the thundercloud down to ground level.