Harvest Supermoon brings SUPER tides!

This week’s night sky gave us a spectacular show,  the Harvest Supermoon, which peaked on the evening of October 6–7, 2025. The Harvest Moon is a full moon that gets its name from the extra light it once gave farmers to finish gathering their crops after sunset. This year’s event was extra special because it was also a supermoon, meaning the Moon was at its closest point to Earth in its orbit. 

When the Moon, Earth, and Sun align during a full or new moon, their combined gravitational pull creates what’s known as a spring tide, when high tides are higher and low tides are lower. Think of the water on Earth being STRETCHED like a slinky from one side to the opposite side! Add a supermoon into the mix, and the gravitational tug gets even stronger, creating what a lot of people in the low country area call king tides. Around Charleston, these king tides are a familiar phenomenon that can temporarily flood roads, push saltwater farther inland, and transform the marshes into expansive seas. NOAA measured the height of the high tide at 7.910ft on October 9th, 2025, perhaps it was slightly higher than the prediction of 7.056 ft due to rain. The actual tide was 2.96 ft. higher than the MLLW (Mean lower low water, or the average height of the lowest tides over 19 years). 

Although flood tides can be dangerous for developed areas, the uninhabited tidal salt marsh becomes a flooded new hunting ground! When flood tides cover the tidal salt marshes, they carry small fish, crabs, and shrimp into grassy flats that are normally dry. Predators like redfish (red drum) and even bottlenose dolphins use these high tides as hunting opportunities, gliding into the flooded marsh to chase prey. While king and flood tides can be a challenge for coastal cities, they’re also a vivid reminder of the natural forces that shape our ecosystems.