Puget Sound is expected to see its lowest tides in over a decade Wednesday and Thursday, 4 feet lower than normal.

Ian Miller of the University of Washington and Washington Sea Grant explained to KUOW that a wobble in the moon’s orbit is nearing its peak, causing the tides to come in and out more powerfully than usual. This oscillation, known as the lunar nodal cycle, will give us the lowest tides in 13 years.

The lowest tide is expected Wednesday noon at -4.28 feet.

Miller said it could give us an extra 6 inches of range that we rarely see.

Over the next few days, beach naturalists will be arranging tours to area state parks including Richmond Beach, Carkeek Beach, Golden Gardens, Constellation Park/Richey Viewpoint, Lincoln Beach, Seahurst Beach and Saltwater State Park.

You can learn more about the Beach Naturalist Program and when they’ll be in the parks here.