Friday, July 27, 2012

Great Lakes Dangerous Currents


Great Lakes Surf Rescue Project
Dave Benjamin, Executive Director of Public Relations, 708-903-0166
Bob Pratt, Executive Director of Education, 517-643-2553


GREAT LAKES, USA – The Great Lakes Surf Rescue Project (GLSRP) wants everyone to know the Dangerous Currents that can exist on the Great Lakes.

Rip currents can occur at any beach with breaking waves.  Waves push water over sandbars toward shore and then that water has to go back out.  Water seeks the path of least resistance.  When a cut in a sandbar appears, water starts to flow out, pulling more sand with it, creating a deeper channel in the sandbar.  Rip currents initially pull away from shore, but may curl and pull parallel to shore once it’s past the sandbar.  There are also several other dangerous currents that may combine with rip currents (e.g. flash rips, long-shore currents, structural rips, and offshore winds.)

Flash rips can appear and re-appear at different locations along the beach, usually during high energy wave conditions. These wave conditions are also called ‘blown out’ wave conditions because the surf is chopped up and torn by strong on-shore winds. When the waves are blown out, they are generally slashed and rippled, creating no discernible breaking pattern (like a washing machine). Flash rips also occur when wave conditions increase suddenly, or during storms, when the water level rises suddenly causing a temporary rip current.

A long-shore current is a current that moves parallel to shore.  Long-shore currents are caused by swells sweeping into the shoreline at an angle and pushing water down the length of the beach in one direction.  It can sweep swimmers into rip currents, piers, jetties, and other hazardous areas. In many cases, the long-shore current is strong enough to prevent swimmers from being able to keep their feet on the bottom, making it difficult to return to shore.  If you try to swim parallel to shore to escape it and you don’t float to asses which way the current is pulling, you will have a 50/50 chance of swimming against the current and drowning OR with the current and escaping.

Rip currents may occur at fixed locations such as groins, jetties, piers, or other man-made structures where water can be funneled out to sea in a narrow channel. In coastal areas with structures, rip currents may result when long-shore currents running parallel to the shore are deflected offshore by the structure.

Looking at all of the 256 incidents on Lake Michigan from 2002-2011, 66% of the cases occurred on a beach with a shoreline structure. That is why it is important not to swim along piers or break walls, because even during seemingly benign conditions rip currents can still exist.

A seiche (pronounced “saysh”) is a sudden fluctuation of water levels on a lake or inland sea. The Great Lakes are among the few regions in the world where these potentially deadly events occur. The simplest definition of a seiche is water sloshing back and forth in a basin; a motion that sometimes resembles a tidal wave.  When strong winds or pressure differences move across the lake, they cause a buildup of water on one end of the lake. As the influencing system leaves (such as thunderstorms, strong cold fronts, etc.), the water will slosh back to the other side, and continue sloshing until it reaches equilibrium. The uneven distribution of water on the shore can cause rip current problems.

An offshore wind is a wind blowing from the land toward the water.  Offshore winds can be deceptive and dangerous on the Great Lakes.  Deceptive because the water may appear flat and calm at the shoreline, but the farther you get from shore, the offshore winds’ strength increases dramatically.

The winds can be especially dangerous for people on rafts, kayaks, standup paddleboards (SUPs), or other floatation devices because the floatation device may get caught in the wind, act like a sail, and be taken far offshore with its occupant.  

Offshore winds can also be dangerous if the person is blown out to open water and the person falls off the floatation device and becomes separated.   In strong offshore winds, a person can’t swim fast enough to catch the device caught in the wind.

One of the most heart-wrenching offshore winds incidents occurred June 2010 when 9 year-old Sofia Khan went missing.  She was in a kayak in Holland, WI and an offshore wind carried her out to open water.  The girl's father tried to swim out to the kayak, but strong winds pushed it farther and faster than he could swim. He was unable to catch up to it and had to swim back to shore.  When the kayak was retrieved, it was empty.  To this date, her body has not been recovered.

Upwelling is a process by which offshore winds push warm surface water away from shore, allowing cold lake water to rise up to the surface from beneath.  Upwelling on Lake Michigan can often surprise beachgoers who arrive at the beach to find very cold water temperatures. The onset of upwelling can occur very quickly, with lake temperatures falling 20 to 30 degrees.  This is very important because cold water shock can cause a person to have a hyperventilating gasp reflex inhalation of water and thus drowning (especially if jumping off a pier).



The Great Lakes Surf Rescue Project, Inc. (GLSRP) is about saving lives.  It is a nonprofit corporation that is a Chapter of the National Drowning Prevention Alliance (NDPA) that tracks drowning statistics, teaches “Water Safety Surf Rescue” classes, and leads the “Third Coast Ocean Force” rip current awareness campaign on the Great Lakes.

It has been selected to present at the 2nd International Rip Current Symposium Nov. 1st, 2012 in Sydney, Australia; the 2012 winner of the “Outstanding Service to the Great Lakes Community” award presented by the Dairyland Surf Classic; the 2011 “Lifesaver of the Year” award winner; and a presenter at the NDPA’s 11th Annual Symposium in San Diego, March 9, 2012.

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