Climate experts are concerned about the frequent occurrence of extreme weather events. In the last five weeks alone, the U.S. has experienced five once in a 1000-years rainfall events, raising concern over the state of the climate. Parts of the U.S. have undergone devastating droughts, yet many parts are grappling with excess rainfall.
On Monday, one such event occurred in parts of Dallas-Fort Worth area where residents woke up to torrential rainfall. In a matter of minutes, they experienced up to 16 inches of rainfall, leading to widespread flooding. At least one person was confirmed dead, according to a report by Washington Post. This event marks a flooding episode that has a 0.1% probability of occurring in any given year. For such a huge event occurring just days after similar occurrences across the states, there is cause for alarm.
In the recent past, such 1000-year rain events have occurred in different places across the U.S., including Kentucky, St. Louis, Eastern Illinois and Death Valley. All of these states were experiencing abnormally dry conditions by the end of July. Out of the blue, torrential floods struck, causing massive damages and deaths.
There are many possible factors behind the extreme flooding occurrences. For instance, the states where extreme flooding has occurred started by experiencing drought. When drought occurs, it leaves the land bare, reducing the ability of the soil to absorb and retain water. Droughts also harden to topsoil, leading to increased surface runoff. When heavy rains fall, these conditions trigger widespread flooding.
While no one can point a direct finger at the exact cause of the floods, all indications show that there is a human hand in the matter. Human actions could impact climate both ways. The effects of global warming can trigger droughts but also cause heavy downpours.
Climate experts worry that if such extreme occurrences continue happening, it will be impossible to predict climate and weather patterns. Previously, meteorologists used data from the past to estimate the probability of certain extreme events occurring. However, climate change is making such predictions unreliable.
Michael Mann, a climate scientist at Pennsylvania State University, explained that such probabilities may no longer apply. For instance, a 2017 paper found that the return period for a 7.4-foot storm flood in New York City had reduced from 500 years to just 25 years.
Via Washington Post
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