Weather Watch

Ocean waves pose danger to surfers, swimmers

Longshore and rip currents can pose a safety concern for swimmers and surfers along the Central Coast coastline.
Longshore and rip currents can pose a safety concern for swimmers and surfers along the Central Coast coastline.

An unrelenting ridge of high pressure over the eastern Pacific Ocean continues to force the storm track north of the Central Coast. 

Not only has this condition produced one of the driest months of March on record in San Luis Obispo County, but it seems likely that it will be the warmest. 

The mean temperature for Paso Robles in March is cool 53 degrees Fahrenheit. So far this month, the mean temperature is nearly 60 degrees. The previous record of 57 degrees was recorded in 2007. 

So for this month, the mean temperature at the San Luis Obispo Regional Airport is 61 degrees or about 7 degrees warmer than normal.  

With abnormally warm temperatures, I’ve noticed a greater number of folks at the beaches. For those venturing into the ocean, longshore and rip currents definitely pose a safety concern, especially with today and tomorrow’s early-season long-period southern hemisphere along our coastline. 

Longshore, or, littoral, currents occur in the surf zone and are caused by waves approaching the beach at an angle. Along most of our beaches, the waves are most often out of the northwest but like today, can also be out of the south. 

If you swim or surf along our beaches where the waves are approaching at an angle, you will most likely become aware of the longshore current as it will push you down the coastline.

In other words, you enter the surf zone at one location and before you know it, you are many yards farther down the beach from where you started. At times, the current can be hardly noticeable; but at other times, it can be quite strong.

Generally, longshore currents increase with increased wave height and a greater angle between the wave crests and bottom contours of the beach.

A longshore current can flow out to sea. I have seen these develop at the down current end of a beach, where a headland (like Morro Rock) deflects the longshore current seaward.

Rip currents are generally narrow and swift-moving streams of water that flow from the beach, through the breaker zone, out to sea, then fan out behind the breakers and become quite diffused.

If you find yourself in a rip current, swim parallel to the beach until you are out of the rip.

Never try to swim against a rip, as you could become quickly tired and hypothermic in the cold waters of the Central Coast.

The strength or location of the rip current is unpredictable.

When they occur, they may be irregularly or evenly spaced along the beach; some of the rips may be weak while others can be quite strong.

Of course, many other currents exist along our coastline: near-surface currents produced by the local winds, tidal currents; the California current, a cold, southerly flowing current that usually occurs during the late winter and continues through the summer months; the Davison current, a warm, northerly flowing current that usually occurs during the fall and early winter months; and the gyres and eddies that derive from these.

For a safe day at the beach, always keep a close eye on your family members and others around you.

Last week, in an effort to help Pacific Gas and Electric Co.’s agricultural customers protect wildlife and prevent electrical outages, the utility provided a grant to install owl nest boxes and vertical wooden poles for farmers in their vineyards. Owls are welcomed by farmers because they help control the rodent population in their fields.  

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