I have a thing for islands. I think you already know that (e.g., St. Martin, Madeline, Beaver, Azores, Dry Tortugas, Vinalhaven, and so on). Barrier island fascinate me in particular. These narrow landforms can be found hugging coastlines all over the world, their sand continuously sculpting by tides, winds and waves according to the elements. They’re ephemeral and they change. This left me to wonder about superlatives. Length? Chains? Erosion? Height?
Longest Barrier Island
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Behold Padre Island’s impressive length. It stretches 113 miles (182 kilometres) from Corpus Christi, Texas to the town of South Padre Island. That’s long enough to make it the second largest coastal island in the Lower 48 United States in spite of its diminutive width. Only Long Island, New York covers more square mileage. Padre Island doesn’t confine itself to a single county either. No, it takes five counties to contain it: Cameron, Kenedy (three cheers for Kenedy), Kleberg, Nueces and Willacy. Somehow I imagine that all of the college students who travel to Padre Island for spring break don’t understand or appreciate that awesome fact.
Longest Barrier Island Chain
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The longest chain of barrier islands is a little more difficult to answer. According to the British Broadcasting Corporation (BBC) "Our Amazing Planet," there are 2,149 barrier islands worldwide. That’s a lot more than previously understood. It’s also worth noting that fact because the longest chain wasn’t even recognized as such until a recent re-examination of barrier islands.
… the world’s longest chain of barrier islands [is] along a stretch of the equatorial coast of Brazil, where spring tides reach 23 feet (7 meters)… The 54-island chain extends 355 miles (571 kilometers) along the fringe of a mangrove forest south of the mouth of the Amazon River. Past surveys didn’t recognize it as a barrier island coast partly because older, low-resolution satellite images didn’t show a clear separation between the islands and mangrove… but also because the chain didn’t match the wave-tide criteria used to classify barrier islands in the United States, where most studies have been conducted.
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According to the National Aeronautics and Space Administration (NASA), the fastest retreat amongst barrier islands at the moment is happening in the Arctic, where apparently a quarter of all barrier islands are located. Traditionally they’ve been protected by permafrost and sea ice (so the barriers have barriers in a sense). However, they get pounded by waves and storms now as their protective shells begin to melt away due to climate change. Barrier Islands along the Beaufort Sea are eroding at levels several times the rate of islands elsewhere.
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I don’t have a good answer for this one. Barrier islands are composed of sand. They will have fairly low elevations by their very nature as they absorb a constant barrage of winds and waves. Sand dunes generally form upon them at the top of the backshore. Jockeys Ridge on North Carolina’s barrier islands, the Outer Banks, is "the tallest natural sand dune system in the Eastern United States." It reaches an elevation of about 100 feet (30 metres). I’m sure there are many contenders for the title so let me pose this one example and see how many 12MC readers can beat it. Please make sure it’s an actual barrier island, though.
It was very difficult to find barrier island superlatives because islands, in general, they tended to drown it out in search engine queries. Can anyone document other superlatives?