Sometimes predictors warn of storms that release these extraordinary rains that are described as 100 years or even 500 floods.
Here is what to know about how scientists determine the extent of flooding and the prevalence of these extremist events.
What does flood mean for 100 years?
Scientists use mathematics to help people understand how unusual normal flooding and how to compare the intensity of the flood to another.
According to American geological surveyOne of the statistical scientists uses the opportunity of the percentage of a specific flood. The 500 -year -old flood means that such an event has one chance in 500, or 0.2 %, from the occurrence of a year.
Another concept that scientists use is the extent to which a certain intensity is expected. For example, the meteorologist can look at the average time break to repeat the expected flood and sees that there is only a similar event every 25 years.
The agencies preferred to express the opportunity of the percentage of flooding instead of the repetition of the repetition because this statistics better represents the fact that rare floods can occur within a few years of each other. It is a kind of rolling a pair of blossom and getting twice twice twice, respectively. It is rare, but it is possible statistically.
There is another term that people hear during an imminent flood is that it can be an event once in the generation or once in a lifetime, which is an unofficial way to say the flood can be unlike anything that many people experience.
How the floods change with the climate
Researchers From the University of Chicago, I calculated that Houston, Texas, was shocked by three floods for 500 years within 24 months from 2015 to 2017. The events included Hurricane Harvey, the heaviest rainy precipitation at all in American homes, business was destroyed and cars were swept away by floods.
Although mathematics can calculate the number of times in which the floods of specific sizes can be expected, nature has its own plans, including violations. Many interconnected systems in the environment, such as local weather patterns and larger events such as El Nino, can change the possibility of floods.
Since the early twentieth century, rainfall events have become heavier and more frequent in most of the United States, and floods have become a greater problem, according to what he said. National Oceanic and Attrads Administration. Gases emitted by humans, such as carbon dioxide and methane, heating the atmosphere, allowing it to do so Carry more water vapor. Victor Jennsini, a professor of science at the atmosphere at the University of Northern Illinois, said that each degree of Fahrenheit has a temperature, the atmosphere can carry approximately 4 % of the water, a 7 % increase per degree of one degree. This steam eventually returns to the ground like rain or snow. “We have absolutely seen a shift in distributing the possibility of heavy rains over the past three decades,” Geninsini said.
Other areas witnessed drought due to changing rainfall patterns. according to NassaThe Great Drought and the excess rainfall periods were frequently occurred. Globally, the intensity of wet and dry events is closely related to global warming.
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Seth Burnstein contributed to this report from Washington, DC
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