Dangerous Currents on the Great Lakes

July 14th, 2014 at 9:20 pm by under Bill's Blog, News, Weather

structural current    The National Weather Service has issued a Beach Hazards Statement for Tuesday.   The Statement warns of high waves, dangerous swimming conditions and strong currents.   There is a danger of longshore currents, rip currents and especially structural currents.  Click on the graphic to enlarge.  This is an overhead view of Grand Haven State Park.   Structural currents occur along the breakwaters of the Great Lakes.  What we often call piers are actually breakwaters.  Technically, piers allow water to flow underneath them.  Breakwaters stop the water and are often along river outlets to prevent sand from filling in the channels.  Structural currents are not a factor on calm days, but can be deadly on windy days.  When the wind pushes the water into a breakwater, the water has no place to go.  It can’t go up on the beach, or up or down.  So a current is created that moves along the breakwater out toward open water.  With a brisk south or southwest wind the dangerous structural current is on the south side of the breakwater (Grand Haven St. Park).  With a northwest wind (which will be the case on Tuesday), the dangerous current is on the north side of the breakwater ( North Beach in S. Haven, Holland St. Park, Muskegon St. Park, Mears St. Park, Stearns Park in Ludington).   The most dangerous place in the entire Great Lakes is the south side of the breakwater at Grand Haven.  It’s more of an issue when a strong south to southwest wind because the air tends to be warmer and more people are in the water.  On days with a strong north wind like Tuesday, the air is usually colder and fewer people are in the water.   Look at the picture here – it’s best to swim well off to the right (south) away from the breakwater, especially on windy days or days with significant waves.  Most of the fatalities in the Great Lakes due to currents are on days when waves are 2-5 feet.  Waves on Tuesday are expected to be 2-5 feet.

There is always a chance of a waterspout when you have cold air coming over warm water.  This is most common from September into early November.   This year, the Great Lakes are colder than average due to both the cool spring and the cool temperatures this July (for the first two weeks of July, Muskegon is 3.7° colder than average and Manistee is a whopping 6.6° colder than average).  Waterspouts are weaker than most tornadoes and tend to dissipate as they come into shore.

11 Responses to “Dangerous Currents on the Great Lakes”

  1. Should be interesting if someone gets a picture on a waterspout tomorrow on Lake Michigan. Although, the NWS seems to think that if there is any there won’t be a whole lot of them (there may be none even).

    1. There may be none that can be seen from shore that is. I am sure there will likely be at least 1 waterspout, but whether it can be seen from land remains to be seen.

  2. fixxxer says:

    Already chilly in allendale. Not a very warm summer at all. I hope august or the fall makes up for this.

  3. Sandy (Hudsonville) says:

    Thanks for the info on the rip currents for tomorrow on Lake MI. It is greatly appreciated.

  4. Barb says:

    I enjoyed kayaking in Lk. Huron by the straits today. It was pretty warm & sunny most of the day until I came home tonight. I ran into some showers sporadically but not a widespread rain.
    My yard in GR is green and full of weeds.

  5. Paul says:

    I don’t know why WOOD TV 8 is ignoring this story. http://www.grandhaventribune.com/article/policefire/1059661

    I hope there is a good end to this.

    1. Rad (Jenison/Hudsonville) says:

      Tue, 07/15/2014 – 3:11am

      Abbie is home safe! According to her dads fb page :)

  6. DarrenSVRstm ( Cedar S ) says:

    My A’s with the best record in baseball and Cespedes brings home the home run derby belt for the second year in a row. Sorry had to mention some baseball as I’m sure not many watched anyways but a crown is a crown….lol. I’m sure my A’s will have there downturn if they do indeed make it to the playoffs and the tigers most likely being there storm saw.

  7. Seaton says:

    I’m sure this is a typo, but the Grand Haven pier is dangerous on the South side (not North) during strong SW winds. Holland is the opposite with strong NW winds creating a strong rip current out flow on the North side. The NW wind usually chases people out of the water given it’s usually a cold front, hence Grand Haven being more dangerous. I’ve been swimming at both beaches for decades (I’m an experienced class 5 white water rafter)and have run into many a rip current at both, but the sheer length of the pier at Grand Haven creates a massive ‘well’ of water to pile up. Rip’s close to the pier can easily exceed 5 knots and are exceedingly dangerous. Tie a rope to your foot and have it pulled by a trolling motor to describe the force. Since people will go in the water irregardless, best advice I can give is don’t go deeper than your waist. The buoys are well past the death zone in 6′ swells.

    1. Bill Steffen says:

      Thanks, Scott – I’ll fix it…south is right.

    2. Paul says:

      According to the NWS website, it’s the northern side this time. So, Bill was right. http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=grr&storyid=103263&source=0

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