China News Service, August 2nd. According to the British Broadcasting Corporation (BBC), since the beginning of summer, extreme weather caused by climate change seems to have become a cruel reality. Local heavy rains have caused many regions around the world to become a country for a time: from Germany and Belgium. , To New York in the United States, and then to London in the United Kingdom, all suffered varying degrees of impact.
A man rowing along a residential area after a flood in Angler, Liege Province, Belgium.
A word often mentioned in news reports is "flash flood", and it is the "culprit" that has caused large-scale traffic paralysis in New York and London.
So what exactly is a flash flood phenomenon?
What is the reason for its formation?
How should people who encounter flash floods respond?
What is flash flood phenomenon?
The so-called flash floods are sudden floods, which are generally caused by excessive rainfall in a certain area in a short period of time, and sometimes they may be caused by massive melting of snow and ice.
The biggest feature of flash floods is that they usually happen suddenly without any warning, and they are fierce.
When flash floods come, the streets will be impassable for a while, people have to abandon their vehicles, and shops and residential houses will be damaged or destroyed due to flooding.
Floods will also affect major public facilities, including transportation networks and hospitals.
Take London as an example. Some hospitals have to ask patients to stay away due to power outages.
On July 15, local time, after a heavy rain in Kyllburg, Germany, the water level of a river soared.
Towns are more vulnerable to flash floods?
Unlike rural areas, rainwater cannot seep into the ground for a while when it falls on the ground in cities.
As urban areas are mostly paved with hard roads, they are more likely to experience this kind of flooding caused by the accumulation of "surface water".
For example, when New York was hit by a hurricane in July, the subway was partially flooded.
Feinberg, head of the New York Transportation Authority, said that this is because the street drainage system has been unable to handle the excessive rain, so the flood water overflows the road.
Water will also pour in from subway vents and stairs.
The sewer systems in most places in the UK, including London, were built in the Victorian era and were constructed based on the historical average precipitation records at that time. On the one hand, they are now old, and on the other hand, they may not be able to continue to adapt to the climate change zone. Extreme weather coming.
Dr. Edmunds Brown from the University of Hertfordshire in the United Kingdom said that the unlimited population growth of London and the continuous expansion of the urban area are also a problem. The Victorian drainage system has been unable to cope with the huge population growth needs.
Are flash floods becoming more frequent?
According to the report, there are many factors that trigger floods, but climate change has increased the possibility of extreme rainfall.
The warm atmosphere can hold more water, thus making the storm stronger and faster.
British climate expert Professor Fowler said that such flash floods were relatively uncommon in the past.
But she said that climate warming means that this kind of short-term heavy rainfall caused by thunderstorms is becoming more and more frequent.
According to Fowler's research, if climate change continues to develop on its current orbit, the flash flood phenomenon-calculated at 30 millimeters of rainfall per hour, will increase by 5 times by 2080.
On July 27, local time, a street in Cernobio near Lake Como, Italy, was flooded after heavy rain.
How should people guard against it?
The town should be able to make some changes to prevent the worst effects of flash floods.
Spert, a flood expert at the University of Reading in the United Kingdom, said that water-permeable pavements can be used in urban areas. They can help absorb rain instead of triggering floods and benefit the city.
In addition, knowing that heavy rains are coming in advance can make flood control easier.
Speter said, "The science of weather and flood forecasting is improving rapidly, and it is now often possible to forecast surface flood events in advance."
The Met Office also recommends that people develop a flood prevention plan, such as moving valuables out of the basement and placing them in a safe place.
Some other preventive measures include: If you want to remodel and renovate your house, choose tiled floors instead of carpets.
At the same time, move the position of the wall socket up.
In addition, motorists must be extra careful to avoid driving when the water level rises, because many deaths caused by flooding occur in vehicles.
Therefore, you should avoid driving on rainy days to avoid danger.