American Oceans

What Is a Sandbar?

Sandbars are a common sight on any beach outing, though these land masses are also found in lakes or rivers. These shallow-water spots often attract many visitors, but what is a sandbar?

ocean and sandbar

This quick guide will cover everything you need to know about sandbars, including what they are, how they form, and where to find them.

Read on to learn more about sandbars and their importance. 

Overview of Sandbars

A sandbar is a ridge of gathered sand that sits off the water’s coast. Sandbars are most common in rivers and oceans, though river sandbars are generally relatively small, and ocean sandbars can be huge.

Mansalangan Sandbar

Sandbars are also commonly referred to as “offshore bars.” 

Because the sand has built up in a sandbar, the sea level is typically low enough that people can stand on the sandbar instead of wading in the water. The sand may be entirely submerged or protrude above the water in some areas, though it’s more common for it to be submerged. 

Sandbars are not permanent fixtures in the water, as they often grow, shrink, and change over time. The presence of a sandbar often depends on the tide, so a sandbar may remain exposed in low tide but disappear in the deeper water as high tide comes in. 

In the summer, sand from sandbars is redistributed to the coastal plains, which is why the coast may seem larger in the summer than in the winter. In the winter, sandbars typically grow when wind carried sand from the coastline comes back into the water. 

Many animals make exposed sandbars their home, especially those who prefer to make their home in shallow lagoons, including turtles, small tropical reef fish, and crustaceans. Coral reefs are a familiar presence in sandbars as well. 

What Do Sand Bars Do?

Sandbars are natural sand formations that may serve as a shallow habitat, signal changing tides, or create an ocean bank.

white sandbar

Ocean banks, also called barrier bars, form parallel to the coastline and build up enough that they surround the beach. The beach is cut off from the open sea as the sandbar forms. 

The ocean bank typically forms in a straight line because of the straight line that waves form in the water. The beach area within the ocean bank has a much lower water level than the open water beyond the bank. 

How Do Sandbars Form?

Sandbars form through sand transport, where water carries sand through waves and currents. As the sand moves through the water over time, larger grains of sand sink into the water.

Langford Island's sandspit or sandbar

Over an extended period, the sinking sand gathers enough to create the ridge or hill of the sandbar. 

A sandbar first forms when a current pushing toward the coast meets a current pushing away from the beach. Where the two currents meet, the water breaks, and instead of going one way or the other, the two pushing forces create a small water column. Any substrate (usually sand) carried forward in the water sinks in this water column. 

For example, bay head bars occur at the mouth of a bay as water pushes out to sea. Like bay mouth bars, underwater tidal deltas, which are fan-shaped deposits of course sediment and sand, are also present in bays and other enclosed bodies of water that ocean water flows into. 

As more sand gathers where the two currents meet, the current’s pull becomes stronger, so the neutral water column widens, and the gathering sand widens with it. Sandbars may appear and disappear over time because of the changing tides and accompanying currents. 

Sandbars in Popular Culture

Since you can sit or stand at a sandbar while surrounded by open water, these land masses have become popular gathering spots for beachgoers.

sandbar in Miami

If the sandbar is exceptionally close to the coast, swimmers will come directly to it, or if it’s farther out, people bring their boats around and park them at the sandbar. 

Sandbar parties have become a staple of beach culture, especially in the United States. Florida is especially well-known for its famous sandbars and frequent events focused on the land. For example, the Crab Island Sandbar in Destin, Florida, attracts thousands of visitors every summer. The sandbar is covered with tourists, locals, live music, and even food and drink options. 

However, it’s not all fun for visitors to sandbars, as there are also inherent dangers associated with the areas. Sandbars are not ever-present attractions; they typically come and go with the changing tide, so visitors should always note when it rises. The currents surrounding a sandbar are often more robust than in regular water, so swimming in the area is more dangerous. 

It’s also essential for visitors to be mindful of the rules, regulations, and laws surrounding any particular sandbar. Many sandbars allow alcohol, but not all do, and visitors should never drive after drinking, as the boat police can issue you a BUI (boating under the influence). Littering of any kind is greatly discouraged because of the delicate ecosystems present in the area. 

Frequently Asked Questions

Here are some frequently asked questions about sandbars. 

What is a sandbar at a beach?

A sandbar at a beach is a sand ridge that forms over time off the coast. The current pushing from the coast meets the current pushing toward the coast, resulting in sand gathering in the spot. 

The sandbar typically has shallow water to walk or sit in, with no need for wading. Sandbars are usually present during low tide and disappear during high tide. 

What makes a sandbar different from a beach?

The beach is where land meets a body of water to form a coast, but a sandbar is formed off the coast of a beach. Straight beaches form from land meeting water, but sandbars form where two currents in the water meet. 

Beaches can consist of various substrates, including rocks and sand, but sandbars are primarily made of only sand. 

Are sandbars dangerous?

Like any area surrounded by water, sandbars carry an inherent danger. Sandbars form when two currents push against each other, meaning the currents surrounding a sandbar are more powerful than in open water. Rip currents are commonly found along sandbars and are one of the biggest dangers in the ocean. 

In smaller bodies of water, the current force isn’t as strong as the ocean waves, but it is still stronger than in open water. Even powerful swimmers are encouraged to avoid swimming along sandbars.

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