| Breakers, Swells and Waves |
| Sometime in the early 1940’s they built the breakwater. The word is that they quarried the stone for the breakwater by breaking off pieces of the Rock – different times, different priorities. The north jetty starts at the Rock and projects almost due south, whereas the south jetty starts on the sand dunes that separates Morro Bay from the open-ocean and projects into the ocean almost due east. The prevailing winds are out of the west and therefore you would expect the north jetty to take the heaviest beating. The opening between the two jetties is the center of our view straight out our window and is the entrance to the harbor.
The first thing we look for is the breaking of the waves on the north jetty. If the swells are heavy, the surf will break against the rocks of the jetty and send clouds of white spray skyward. The waves seldom hit the jetty straight on and so the spray will start at one end and run the length of the breakwater, sort of like a zipper. This only happens if the “surf is up”. The next area of focus is just south of the south jetty. We can see a little of the sand beach and the surf pounding, if there is any significant wave activity. There are days when we can hear the surf. There is a low roar that sounds like a distant train. The roar is so constant that, at first, it is hard to identify – its just background noise. But, once you identify its source, it becomes obvious and is an indicator of the wave height. Most of the time the surf is pretty quiet, but like the local surfers, we are always on watch. The breakwater is also in indication of the local tide. The tide here runs as much as eight feet. By observing the height of the jetty above the channel, we get an indication of the state of the tide. This isn’t earth shaking information but sometimes knowing the tide influences decisions. The biggest affect of the tide is on the estuary of the bay south of here. High tide makes the estuary a beautiful watery bay - low tide drains the whole area and leaves a huge mudflat. Swells and the waves aren’t necessarily the same. The swells that have the biggest influence on the surf may have come from as far away as the Gulf of Alaska and they may be a residual of a storm that occurred days ago. The waves that ruffle the surface of the water, and can make the white caps are due to the local winds and their contribution to the surf is usually less significant. Because all of the traffic in and out of Morro Bay must pass though the gap in the breakwater, we can keep an eye on what’s happening. A more interesting coming has been a replica of the Nina, one of the smaller of the three ships used by Christopher Columbus. The Nina has been tied up along the waterfront for several months now. They want five bucks to go on board, but so far I haven’t had five bucks worth of curiosity. There is a Coast Guard Station near the mouth of the harbor. They have a fleet of small boats with the biggest being a pair of “Motor Lifeboats” about forty-seven feet long. Almost every day the Coast Guard has some sort of a training exercise. Its hard to tell from here what exactly they are trying to do, but a typical exercise is for the two Motor Lifeboats to go out in the open ocean and for one of the lifeboats to tow the other one back into the harbor. |
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| Each morning, as we get out of bed, we head for the window to check the weather and the world. Our view from our window is of Morro Rock and the entrance to the harbor. Our view of the Rock tells us just how foggy it is. This was important to us the first couple of weeks in residence. As we entered the fall and the overall weather became less foggy the harbor entrance has become more of our focus. On really foggy days we can’t even see the harbor much less its entrance. |
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| At the Coast Guard station, out on one of the docks, is a sign that looks like a highway yellow diamond shaped information sign that says “rough bar”. In spite of the first perception, the sign doesn’t refer to a shady establishment whose business is to dispense watered-down rum. All kinds of things happen at the point that a river or estuary empties into the ocean. This interface is called a “bar”. If the river is heavily laden with silt, hitting the salt water causes the slit to precipitate out creating a shallow area. Silt is held in suspension in rivers electrostatically (and other mechanisms.) Salt water is more conductive electrically than river water, so upon entering the ocean the silt is discharged and fall to the bottom.
As swells move across the ocean, the waves become higher and rougher as the water gets shallow (that what makes surf). Because the silt builds up at the river mouth, making it shallower, the waves get bigger. Also as the water of the river (or estuary) rushes into the ocean there is a crash with the still or natural ebb of the ocean water. This shallow water waves and the crash of the outflow can create a standing wave at the harbor entrance. At one time we raced small sailboats. One of the races was at Santa Cruz; we sailed out of the local yacht club. We had left the boat harbor in the morning without incident, but on returning in the afternoon we found a huge standing wave at the harbor entrance. We looked down into the relatively small harbor entrance from what seem to be at least a height of twenty feet (two stories). There was no breaking water, just a steep hill. It was a thrilling ride. We got into the harbor safely, but if I could figure out how to get to top again – I would love to do it again. This was my first direct experience with a rough bar. Several years ago, I was invited to go on a party boat, out of Morro Bay, for albacore. We boarded a fairly large charter boat (120 feet or so) at two o’clock in the morning. The water in the bay was glassy smooth. As we approached the entrance to the bay there was a standing wave that pointed that whole boat straight up in the air. I was shocked and amazed, but did learned to respect rough bars. We can see that same harbor entrance from out window. So far we only have seen a couple of times that this standing wave is a hazard to small boats. When this condition exists the Coast Guard sends out its lifeboats and they blockade the harbor. They hold the incoming boats offshore until they feel its safe to enter. There has be one news program that reported an SCARB (Small Craft Advisory for Rough Bar) for Morro Bay. We looked out to see what might be happening but saw nothing unusual. |
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| Coast Guard station docks near the mouth of the Harbor - Notice the yellow "Rough Bar" sign and the weather warning flags |
| Overview of the harbor entrance and seen from the top of Black Hill. Coast Guard Station is just to the left of the three smoke stacks of the power plant Standing on the North Jetty looking south - no Breaking Surf on that day |