Photos courtesy of the Outer Banks Visitors Bureau
Life on a sandbar can be pretty interesting at times. And that’s what the Outer Banks essentially are—giant sandbars.
There isn’t anything that really anchors them in place. Humans have done a remarkable good job of stabilizing them, but it’s still a very dynamic environment.
As evidence of this, we present Shelly Island.
Shelly Island won’t show up on any maps of the Outer Banks, at least not any map that wasn’t made in the past three months. But it’s there, curving gracefully around the point in Cape Hatteras (commonly referred to as the Point).
The formation of a new island along the Outer Banks is rare but not unheard of. Typically, they’re temporary, lasting maybe a three or four months. What seems to have generated much of the interest in Shelly Island though, is its size—a mile long and about 500-900’ wide.
According to an NPR interview with Dave Hallec, Park Supervisor for Cape Hatteras National Seashore, the island had been forming for some time.
“I was looking at some aerial photography from earlier this winter around February, and you could see the island underwater,” he told the interviewer.
It’s difficult to know exactly what happened to create this new island, but there are some things we do know about barrier island dynamics and the Outer Banks in particular that may help explain how Shelly Island came into existence.
Because barrier islands are not actually anchored to anything, the sand that makes up their mass is in constant motion. As sand moves through the ocean, it is referred to as sand transport. The sand transport that passes the Outer Banks is as great as any barrier island chain in the world, and may be the largest.
Generally the sand moves from north to south until it gets to Cape Hatteras. Sticking out like a knobby elbow into the Atlantic Ocean, the Outer Banks takes a southwestern track at that point.
There are a number of environmental factors at play at the Point. This is where the Labrador Current and Gulf Stream meet—although there are some seasonal variations in terms of where that actually is. Cape Hatteras is the above water part of Diamond Shoals, a vast area of shallow waters covering shifting undersea sandbars.
Conditions would seem ripe for the formation of something like a new island. We know from years of observation that Outer Banks beaches regularly lose sand, then accrete, or gain sand.
Added to this mix are eddies that spin off from the confluence of the Labrador Current and Gulf Stream. There is still much that is not known about the eddies, but what is known is that as the eddies lose energy, any material that has been picked up—including sand—precipitates out.
What Shelly Island may represent is a perfect storm of circumstance. Jutting out into the ocean as it does, the Point is already at the ideal place to capture material; if an eddy had moved extra sand to the area, there could be enough to create a new island.
It’s all speculation, of course.
The island is separated from Cape Hatteras by a channel that is about 50 yards wide. At low tide it’s easy to cross. At high tide it is dangerous. The current is very strong, sharks and large stingray have been seen in the channel, and a number of people who walked to the island at low tide have had to be rescued, usually by kayakers.
The name? How the island got its name is interesting. According to a number of reports, soon after the island formed, a grandmother took her grandson to it. There were so many shells and in such good condition that the grandson dubbed it Shelly Island.
We don’t know what the fate of Shelly Island will be. Typically this type of island is very temporary and may disappear by this time next year. Or, the channel separating it from the Point could fill in and Cape Hatteras may have extended farther into the sea.