For Today’s Japan Photo, we take a look at this interesting natural phenomenon of tidal whirlpools in the Naruto Strait, a channel between Naruto in Tokushima and Awaji Island in Hyougo, Japan.
Due to the narrowness of the strait, the water rushes through the Naruto channel at a speed of about 13–15 km/h (8–9 mph) four times per day, twice flowing in and twice flowing out. During a spring tide, the speed of the water may reach 20 km/h (12 mph), creating vortices up to 20 m (66 ft) in diameter.
