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This is the time of year when things start to really shift. Trees go from green to gold, shorts are traded for pants, and then there is the wind. With the change in season, there is a loss of equilibrium between water and air temperatures. The still-warm water, holding on to summer sun, radiates a bit of that heat from its surface, creating a low-pressure area for cool air to swish in. The often-predominant southerly breezes become northerly. Fall’s complex patterns remind us of how many factors contribute to the movement of water.
One particularly breezy morning, my nephew who was visiting asked me if he needed to worry about rip tides in our bay. We talked a little bit about what a rip tide is. It is most often a concern on long, wide, open beaches — not in a small, enclosed cove.
“But you have really big tides here?” he asked. This made me pause. I realized what he was thinking: Big tides = possible rip tides. I didn’t think rip tides had anything to do with tides, but now I had to look into it.
Part of the answer to my nephew’s question lies in an alternative phrase often used to describe a rip tide — a rip current. These terms are not mutually exclusive since a tide, when moving in one direction or the other, results in a current. If you have ever been swimming or boating in the direction opposite to the flow of the tide, then you already know how strong a tidal current can be. This is particularly pronounced in narrow coves, where the movement of water is channeled through a small area.
Tidal currents are not to be taken lightly and are important to consider when going out on the water. However, they are also relatively predictable. Simply checking a tide chart can tell you which direction the water will be moving — in or out. And if you want to avoid the period of highest tidal flow, you can choose the window of time on either side of a high or low tide, also known as “slack tide.”
A rip current is a different beast. It does not behave according to predictable rules, and it is not always easy to identify and avoid. Rip tides most often occur in areas with waves breaking along the shore. As the waves topple, they bring lots of water to the shore. When that water rushes back out to sea, it creates a strong pull. This movement can pull unwary swimmers right along with it, out and away from the shore.
The shape of the seafloor can impact rip currents. Just like a tidal current is stronger when channeled through a small area, the same is true of a rip current. If there is a little underwater channel of sorts, it will create a more concentrated rush of water.
As elusive as rip currents can be, there are ways to spot them. The simplest is to notice a difference in the water pattern or color on the surface. For example, if the fast-rushing water is going through a deeper channel, you can see the quick water movement on the surface, as well as a darker color resulting from the water depth. Nearby areas may look more calm and even. Unfortunately, this isn’t always easy to see from the surface, but lifeguards can sometimes spot rip currents from their towers or using drones.
There are some practical ways to respond if you find yourself caught in a rip current. Because the current is caused by an area where the water is funneled quickly, that means that once you get far enough from the source, the current will be less powerful. Instead of trying to swim against it, you should swim along the shore until you can feel that the water is calmer and you are able to get back onto land.
Whether tide- or wind- or wave-caused currents, the humbling lesson is that water is really powerful. At this time of year in particular, conditions can change quickly and without much warning. It is somehow a comfort to know that nature is so much more powerful and impressive than we are, and that reminds us to be more humble when we head out on the water.
