Nova Scotia is blessed with beautiful beaches. These beaches, however, experience some of the most powerful surf on the Eastern seaboard. There is only a limited amount of time on the beaches for Nova Scotians to experience and learn how the ocean works. Due to this limited time, most Nova Scotians and travellers to Nova Scotia have minimal knowledge of the dangers the surf has to offer.
Movement of the water coming on to the beach from waves cause certain on-shore currents commonly known as rip currents (sometimes referred to as "rip-tides", "undertow", "wash" or "run out"). Rip currents are mainly caused by an outward flow of water that is returning to the sea which form by waves washing up on shore. After washing on shore, gravity forces the water to return to sea. Depending on the force of the wave, beach conditions and location of sandbars under the surface, the water that is returning to sea may accumulate in one concentrated area, causing a strong current at an isolated zone of the beach. The larger the waves washing up, the stronger and more dangerous the rip currents will be. Rip currents can stay in the same place for long periods of time (6 months to a year), travel along the length of the beach, or suddenly open at any time or location along the beach. Here are some signs to help you distinguish a rip current:
How to Escape from a Rip Current
Any of the Provincial beaches which are supervised by the Nova Scotia Lifeguard Service (NSLS) use internationally recognized lifesaving flag system. The red and yellow flags are used to identify to the public the safest location on the beach to swim. The NSLS does many rescues each year with the majority of the rescues occurring outside the flagged area.
What makes the flagged area the safest?
Tides have a large influence on currents around beaches as well. Generally the seas reach their highest level on shore twice a day. The average interval between 2 successive tides is 12 hours and 25 min. As the tide drops there are many salt water lagoons that will empty out to stay level with the ocean which in turn cause tidal rips. As the tide runs out the large amounts of water that was brought into the lagoons must return to the sea which causes currents to flow like rivers. As the tide ebbs, this causes the same effect as the water rushes in to fill the lagoons. An example of this would be the channel at Rainbow Haven Beach and Mira Gut Beach.
Surf or waves are formed by winds blowing over the ocean generally caused by storms at sea. There are three factors that affect the size of the waves;
When waves approach the shore, they approach in a group of waves called "SETS." Sets are swells that are produced by storms at sea and travel across the ocean. These sets are larger than your average waves produced by a storm. The number of waves produced in sets and lulls between are consistent for a given swell but varies between swells. As the waves approach shore two things happen. First, the wave slows due to the friction with the ocean bottom. Second, the wave raises (wave height increases) and eventually breaks when the water is shallow enough.
There are four different types of waves:
Dumpers or Plunging Waves
These waves occur when waves encounter and abrupt change in depth (from deep to very shallow) and break with immense force. These usually occur at low tide when there's less water for the wave to break into or at beaches where the slope of the beach is steep. They can easily slam swimmers to the bottom (sand, rocks, coral...etc).
Spilling or Rolling Waves
These waves occur when the change from deep to shallow is more gradual. When these waves break, the wave peaks and the water spills down the face of the wave, along the length of the beach. Although less intense than the "dumpers" they are still powerful and can knock swimmers over and knock them under the surface.
Surging waves may not actually break as they approach shore, but simply surge up onto the beach/rocks and then quickly flow back out to sea. They can be particularly dangerous to young/infant swimmers because they can knock them off their feet and wash them out to deep water.
Although under certain circumstances abnormally large waves, called episodic waves of 100 feet plus, can occur; the concept of rogue waves is widely misused and misunderstood. Most of us will never see a episodic wave, such as a tsunami, as they only occur in certain areas and under rare conditions. What the public normally mistakes as a rogue wave are simply a large set of waves in a swell. Swimmers or anyone walking near the shore must always remember that the size of the next wave is unpredictable.
In Nova Scotia generally the seasons with the highest surf are late summer/fall (atlantic hurricane season) and the winter. During these periods intense storms in the atlantic create dangerous surf conditions as they meet our shores. This is especially important this year due to the number of beginners brought into the sport of surfing. Everyone should take special precautions during these times as there is limited supervision on the beaches.