Pillsbury Sound

Pillsbury Sound
Pillsbury Sound

Yesterday Habiba, Jacob and I were returning from a day on St. Thomas using our usual mode of transportation, our beloved 15-foot Carib hard-bottom inflatable, named SeeStJohn. We left Sapphire Bay marina just before sunset bound for Great Cruz Bay on St. John. The sky was crystal-clear in the southeast while the north was dominated by the gray skies produced by a passing rain squall, where a double rainbow touching down at Thatch Cay rose high into the sky and completed it’s arch in the blue skies of the Caribbean just south St. John. Behind us the sun was beginning to set.

A lot has changed on St. John since I first arrived here in 1970, but what has not changed is the sheer physical beauty of not only St. John, but of all the Virgin Islands, both American and British.

Pillsbury Sound
Pillsbury Sound Sunset

From the majestic panoramas of islands and seas, harbors and towns, to the verdant valleys of lush tropical forests, this beauty is all around us and I’d be hard pressed to compare one with another.

But right up on the top of the list of favorites would be the Pillsbury Sound, the stretch of water separating St. Thomas from St. John and the Caribbean Sea from the Atlantic Ocean. (See article on Virgin Islands Geography)

I would highly recommend that visitors to St. John include in their itinerary a sunset cruise on Pillsbury Sound.

The Islands and Cays Surrounding Pillsbury Sound
Forming the limits of Pillsbury Sound are not only St. Thomas and St. John, but several other smaller islands.

On the north are a line up of long narrow cays, the largest being Thatch Cay, and including Grassy, Mingo, Lovango and Congo Cays, of which only Lovango is inhabited. between Lovango and St. John is Henley Cay

On the south are Great and Little St. James and Dog Island.

There are two small private homes on Great St. James. Last year plans submitted for the construction of a high-end housing community on the island were denied by the Costal Zone Management (CZM) due to environmental and ecological concerns.

Little St. James has recently been in the news in conjunction with a sex scandal involving underage girls ferried to the island to perform massages for the billionaire owner of the private estate.

Pillsbury Sound is both static and dynamic. While the islands, which encircle the sound stay in pretty much the same place, except for the drifting of the Caribbean and Atlantic plates, the sound itself is ever changing. The most obvious changes are the colors. On a clear day the theme is blue, white and green; blue water, white clouds and green islands. On stormy days everything, islands skies and seas are steel gray, and on days when dust from the Sahara Desert of ash from the Montserrat volcano fills the air everything seems white and far away.

Waves and Currents
On some rare days, the seas will be flat calm on others there may be tall steep waves and strong currents. The change in sea conditions within the sound is more pronounced than the usual changing conditions of the seas elsewhere. This is because Pillsbury Sound lies between the Atlantic Ocean and the Caribbean Sea.

These two great bodies of water average about two miles deep with depths in some areas as great as 28,000 ft more than five miles down. The waters of the Pillsbury Sound are about 100 ft deep. As the moon revolves around he Earth its gravitational pull exerts its influence over the great seas causing a bulge of water to follow the moon on its path. This is called tides. Twice a day the tide causes this bulge of water to flow from the Caribbean Sea to the Atlantic Ocean and twice a day the reverse occurs bring Atlantic Waters into the Caribbean. To do this in the vicinity of the Virgin Islands the water must squeeze between the Islands. The places where this happens are generally called “passages.” The Pillsbury Sound is one of these passages.

Here’s a cool map that shows the Caribbean and Atlantic basins and the partly underwater mountain ranges, which are the islands of the Greater and Lesser Antilles. You can even move the map around.

This huge volume of water moving from the Ocean to the Sea and back, squeezing between St. Thomas and St. John, a passage just about two miles wide, passing over the equivalent of a 28,000 foot high mountain range can result in steep waves and strong currents. These degree of surface water conditions caused by the tides depend on several factors. During full and new moons, when the gravitational pull of the moon combines with the pull of the sun, the effects are greater than than in mid cycle when the pulls of the two heavenly work against each other. The time of day is another factor. As the moon passes and exerts its gravitational pull on the waters around the Virgin Islands, this pull gets weaker as the moon moves farther away until it is lost and the water recedes in the opposite direction. During this time, called slack tide, tidal effect are minimal. The third major factor are the atmospheric conditions, that is, the winds. Wins also create waves and the interaction of the two forces may work with each other or against each other. If the wind and the tides cause waves in the same direction, the result will be long gentle swells, which are relatively far apart. If they work against each other, the waves will steepen and be closer together.

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