The term ‘King Tides’ is not a scientific term, but a way people describe the most notorious high and low tides of the year. Why notorious? These tides leave a precedent for future tides to exceed and can create destruction to cities nearby coastal areas. As Earth’s temperature increases due to global warming, sea levels are rising and causing these tides to inch closer and closer to people’s door steps.
To understand why king tides occur we must understand why tides happen in the first place. You might’ve heard that the moon controls the tides, why is that? The moon, like Earth has a gravitational force. It’s close proximity to Earth allows the moon to use its force and try to draw Earth closer. Of course the moon can’t bring Earth closer as it’s astronomical size is too large, but it does have an influence on Earths oceans. As the moon tugs on Earth it is compressing it or stretching it horizontally. When Earth is compressed it causes its water to squeeze out on its sides, pushing more water out on two sides and leaves the other sides with less water. This creates two high and low tides that Earth rotates through in a day.
While looking at this diagram it’s important to remember that earth rotates on its axis. If you look at it that way you can see how Earth passes through these high and low tides each day.
Now we’re aware why tides occur, but there are special occasions where tides can become greater. When the Earth, Moon, and Sun align, tides become higher than normal. The Sun, like the moon, has a gravitational force, yet it’s influence on tides is lesser than the moons because it’s distance isn’t nearly as close. When these two gravitational forces combine, their strength is enhanced. Earths water extends out further creating noticeable higher and lower tides called spring tides. This alignment occurs twice a month when there is a full or new moon.
But what causes a KING tide?
We know the moons gravitational pull causes tides to occur on a regular basis and that special occasions like the alignment of the Earth, Moon, and Sun creates larger tides. Yet there’s an even greater event that creates the biggest tides of the year. If you thought that the Earth and Moons orbit is circular, that is incorrect. It has been found that all large planetary objects that orbit actually travel in an oval path called elliptical orbit.
In Earth’s orbit around the Sun, the Sun isn’t directly in the middle but it’s located closer to one side of the orbit. When it’s farther Earth’s orbit is called aphelion and when earth is closest it’s orbit is called perihelion. When Earth is in perihelion the Sun’s gravitational force can impact Earth significantly. The combination of the Sun, Moon, and Earth’s alignment along with a closer distance to each other creates the King Tides. Tides during this time will still be significantly higher, but when this perfect conjunction occurs it calls for the KING of Tides. This years California King Tides will take place on January 22-23.
Rare occurrences in nature are thought of as phenomena’s and beautiful and they certainly are, but these tides keep challenging each other to grow higher and higher as more freshwater from glaciers are dissolving and increasing sea levels. This can be terrifying if you live near coast areas since flooding, power outages, and destruction of buildings often accompany these tides. If you’re interested you can contribute to scientific data and research on king tides by going out to your local beaches and taking images of extraordinary tides or any damage you see around your city/town caused by king tides. You can submit your photographs to the California King Tides Project. These photos will be used be used in presentations, exhibitions, websites and publications on sea level rise impacts, coastal initiatives, and climate action. https://www.coastal.ca.gov/