If you live near the ocean, you may notice larger than normal tides this week.
On October 6, at 10 a.m., the Moon will be at its closest point in its orbit relative to the Earth. Astronomers call this position “perigee.” The following day, October 7 at 2:44 p.m., is the New Moon, which is also the time when the Moon is closest to the sun.
Because the Moon is at perigee near the time of the New Moon, the Earth will experience exceptionally high tides.
Any time the Earth, Moon, and Sun form straight line, larger than normal tides, called spring tides, occur. The word “spring” has nothing to do with the season, but rather is from the German “der springen” meaning to “spring up,” since that’s what the tides tend to do during times of full and new moon.
When the Moon is also near perigee, its pull on the ocean is even stronger. And when it’s on the same side of its orbit as is the Sun, both tug on the oceans from the same directions, resulting in a very strong and high tide. This super high hide is called a “proxigean spring tide.” The Earth experiences proxigean spring tides no more than once every 1.5 years.
Proxigean spring tides can be dangerous if a big ocean storm is offshore. Because tide levels are much higher than normal, even without a storm, these tides can often result in widespread flooding.