There are high tides, and then there are even bigger ones. To coastal observers, these extremes are known as King Tides, the non-scientific term used to describe exceptionally high tides.
And they’re coming.
King Tides normally occur during a full moon and when the moon is at its perigee, i.e., when it’s closest to Earth. The next time a King Tide will occur is January 11-13, 2021.
Coastal projects in Washington, Oregon, and California are preparing for the surging waters of the Pacific Ocean, while North Carolina, Florida and other Atlantic Coast states are also getting set. The groups are looking for assistance in documenting the high tides to help them predict the future.
King Tides can cause unusually high waters, which leads to flooding. According to the Environmental Protection Agency, this is a sign of things to come.
“Over time, sea level rise is raising the height of tidal systems,” the EPA explains in a fact sheet (PDF) on the subject. “Average daily water levels are rising along with the oceans. As a result, high tides are reaching higher and extending further inland than in the past.”
This could be alarming for coastal towns and areas.
“As time goes by, the water level reached now during a King Tide will be the water level reached at high tide on an average day,” the EPA says.
How concerning is this? Climate scientists are alarmed.
“California will be greatly impacted by sea level rise,” according to the California King Tides Project. “For example, San Francisco is projected to see a rise between 1.1 and 2.7 feet by 2050, and by 2100 could experience between 2.4 and 6.9 feet of sea level rise with a potential for more than 10 feet of rise if there is extreme melting of the West Antarctic ice sheet.”
Rising tides will also impact areas of the coastline where there isn’t development.
“Rising sea levels means increased erosion and more frequent and expanded flooding in the future,” according to the Oregon King Tides Project. “An infrequent event today could become normal in the future.”