Why are the waves in Lake Michigan so big?

The science and danger behind large Lake Michigan waves

CREATED Oct. 30, 2012 - UPDATED: Oct. 30, 2012

  • Print
  • Jesse Ritka reports Video by tmj4.com

    video

MILWAUKEE - We're feeling the wrath of Superstorm Sandy right here in southeast Wisconsin.  It's not the rain but the wind and the waves that are causing problems here as a result of the hurricane.

Gene Bliss tells TODAY'S TMJ4's Jesse Ritka he heard how bad the waves were going to be and decided to drive to Lake Michigan's shoreline to check it out, "I came out to see the waves and see how bad it was."

The waves attracting an ebb and flow of onlookers like Bliss at Lake Michigan are a result of northerly winds surging around the remnants of Sandy as she moves west.  "It's amazing, I've never seen anything like this, ever," Bliss remarks.

But the waves are expected to get even bigger with time because of three factors: strong winds, a long period of time and a large fetch, or distance the wind must travel.  The waves may start off looking small in the northern waters of Lake Michigan, but traveling 300 miles straight down the entire length of the Great Lake, the energy is compacted into a smaller space, which creates a much larger wave.

"As the shoreline gets closer and closer and the water gets more shallow, the same energy is there but the energy is compressed," Discovery World's Richard Cieslack explains.

Gale force winds between 39 and 54 miles an hour are known to create deadly waves.  "There have been a lot of ships that have gone down in Lake Michigan due to storms," Cieslack says.  One famous car ferry, the S.S. Milwaukee, could not overcome a heavy gale in 1929 and sank, taking more than 50 lives along with it.

But watercraft today seem to be heeding the warnings, especially where it is most dangerous in the southern tip of Lake Michigan.  "They take more of a northerly brunt, they'll get hit a lot harder, in our case the waves are a little lesser out here because the wind's from the north and we're facing east," Cieslack says.