When everything also slopes towards a watercourse, you get this type of "flashfloods", she explains and points out that exactly how it could go so badly is still difficult to explain and will require longer analyzes.
This storm has stopped in one place and the very intense precipitation has fallen very locally. The fact that it occurred at night, when people were sleeping, has made the consequences even more catastrophic.
Whole summer
In just a few hours, a rainfall equivalent to a whole summer's precipitation fell, according to CNN, and flowed down along the Guadalupe River in the area around Kerr County. The downpour started during the night to Thursday and surprised many of the camping people in the natural areas around.
At least 82 people have died, including 28 children, and over 40 people are still missing.
Meteorologists can predict quite well how much precipitation will fall, but the difficult thing is to say exactly where it will come and to hit the right time, says Nina Bosshard.
Greatest risk in the mountains
The places in Sweden where similar flash floods can occur are in the mountains.
We saw that when the Susabäcken in Åre overflowed two years ago. It was also a "flashflood" but thankfully not as large a watercourse. It is when there are steep slopes and clear valleys that the risk is greatest. The same amount of precipitation can fall in southern Sweden, but a flood does not occur nearly as quickly.
The risk of this type of weather also increases in general due to climate change.
A warmer atmosphere can hold more water vapor and warmer oceans also evaporate more water vapor. Then there is much more water in the system, so the potential for heavy precipitation becomes higher, says Nina Bosshard.
Fact: Severe floods in recent years
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October 2024, Spain: Over 200 people died when large amounts of rain caused flooding in eastern Spain, mainly in the Valencia region.
September 2024, Nepal: Floods plagued the mountainous country in July, August, and September. The consequences were most devastating in September when at least 224 people died in floods and landslides.
April 2022, South Africa: Over 400 people died in the floods in the KwaZulu-Natal region on South Africa's east coast after heavy rain. The damage affected, among other things, the million-city Durban.
July 2021, Europe: Several countries were affected by floods when rainstorms swept over Europe. At least 190 people died in western Germany and nearly 40 in Belgium.
