The meteorological term makes Trump misunderstand about super typhoon Harvey

Trump's sharing on social networks misunderstood the flood after the super typhoon Harvey "500 years only" but in reality it was not.

After Hurricane Harvey hit Texas, US President Donald Trump posted a tweet saying super typhoon brought "a new 500-year flood once" to Houston and expressed support for the August 27 relief efforts. , according to the New York Times. Trump's misinterpretation of this natural disaster has never appeared in the area for five centuries. But some parts of Houston experienced similar scale flooding last year. In 2001, Tropical Storm Allison also caused major flooding across the region.

Houston, Texas streets, heavy flooding due to super typhoons.(Photo: The Feed).

Harvey may have greater destructive power and the authorities also stressed that this is the worst flood in state history. Terms such as " 500-year flood " (500-year flood) and " 100-year flood " (100-year flood) are used by government officials and statisticians to use as a shortcut , but those are misleading terms that are easy to mislead the public, according to Sandra Knight, senior research engineer at the University of Maryland, a former employee of the Federal Emergency Management Agency (FEMA).

The above terms refer to the possibility of flooding, not the predicted time of flooding. 500-year flood with 1/500 is 0.2% of the possibility of the year. In other words, this type of flood is less likely to occur based on historical data. Meanwhile, 100-year floods have 1/100 or 1% likelihood, meaning this is the kind of flood that will occur in an area every year.

Map of Houston flood areas created by FEMA. The map shows areas that could be affected by 500-year floods and 100-year floods.

Map of flood areas of Houston.(Photo: FEMA).

In Houston, factors such as rapid urbanization over the past few decades have affected the amount of flood water and where it occurred. Climate change will also enhance the likelihood and severity of future extreme weather events.

Great destructive storms like Harvey are still relatively rare. " But their likelihood is increasing dramatically due to climate change. The 500-year flood event will become a 100-year event, " said Kevin Trenberth, scientist at the National Center for Atmospheric Research. Boulder, Colorado, said.

The United States National Oceanic and Atmospheric Administration has not officially classified hurricane-flooded Harvey as a 500-year flood. However, certainly this type of flood could reappear before 2517.

Heavy rain caused by historic Harvey storm in Houston.(Video: New York Times).

Super typhoon Harvey level 4 landed Texas late August 25, causing heavy rain and strong winds, destroying many homes and causing serious flooding. The storm caused at least 5 deaths. Houston television said the floodwaters swept away trucks that drowned six people.