Moon Wobble Could Cause Coastal Flooding


NASA has warned that nearly all coastal areas in the US mainland could see a surge in high tide floods by the mid-2030s. By that time, a lunar cycle will amplify rising sea levels causing a dramatic surge and flooding. High tide floods are known as nuisance floods or sunny day floods and are already a problem for some cities on the Atlantic and Gulf coasts.

According to a recent NASA study, the alignment of rising sea levels with a lunar cycle will cause increasing floods of this type. Low-lying areas near sea level are increasingly at risk and suffering due to the increased flooding, and it will only get worse, said NASA Administrator Bill Nelson. The combination of the Moons gravitational pull, rising sea levels, and climate change will continue to exacerbate coastal flooding on our coastlines and across the world. NASAs Sea Level Change Team is providing crucial information so that we can plan, protect, and prevent damage to the environment and peoples livelihoods affected by flooding.

The main reason for the increased flooding for some coastal cities is because, during half of the moon’s 18.6-year cycle, regular daily tides are suppressed. High tides are lower than normal and low tides higher than normal. And the other half of that cycle, tides are amplified.

Currently, the moon is in the tight-amplifying part of its cycle. NASA says that most US coastline has sea levels that haven’t risen much that even with the lunar cycle, the high tides regularly top flooding thresholds. However, the next time the cycle comes around again in the mid-2030s, the story will be different.

From a planning perspective, its important to know when well see an increase, Hamlington said. Understanding that all your events are clustered in a particular month, or you might have more severe flooding in the second half of a year than the first thats useful information. A high-tide flood tool developed by Thompson already exists on the NASA teams sea level portal, a resource for decision-makers and the general public. The flood tool will be updated in the near future with the findings from this study.