Moon Could Help Trigger a Decade of Flooding

Flooding in the 2030s might make us look back fondly on this decade. NASA sea level researchers say high tide flooding could seriously worsen next decade along US coastlines, NPR reports. That's the sort of flooding in which water invades streets and yards in coastal areas. "Nuisance floods," as they're sometimes called, take place when tides hit about 2 feet above the daily average high tide, per Live Science. If they don't last long, damage is minimal. But a peer-reviewed study published in Nature Climate Change finds the flooding could occur more often and be more serious, possibly for the entire 2030s. Rising sea levels caused by climate change is a big reason. "They're getting awfully close to the brim in coastal communities due to decades of sea level rise," said an oceanographer who co-wrote the study, per the New York Times.

The spark could come from the moon. It operates on an 18.6-year cycle, creating lower high tides and higher low tides half the time and higher high tides and even lower low tides the other half. The moon will be due to "wobble," and its influence on tides will be more dramatic than in the past because sea levels are so high, the study says. The effect will vary along different coastlines. In addition, researchers wrote that floods could start occurring in clusters lasting a month or so, depending on the position of the moon, sun, and Earth. The wobble itself doesn't have a huge effect usually, moving high tide at a beach by an inch or two over the cycle. But the factors add up, and researchers say we shouldn't be caught by surprise. "It just kind of raises the baseline," said the study's lead author. "And the more your baseline is raised, the smaller weather event you need to cause a flooding event." (More flooding stories.)