Muskegon Chronicle

Big Lake ‘tsunamis’

   A November 2001 seiche on Lake Superior caused water levels to rise 1.5 feet in Duluth, Minn., and was followed by strong winds and high waves. These photos, taken minutes apart, show how the water rose quickly in Duluth’s Canal Park.

   Thousands of tourists crowded the scenic beach to enjoy a long holiday weekend, unaware of the approaching tidal wave that would sweep them into a deadly natural disaster.

   That was the scene one month ago, when a killer tsunami raced across the Indian Ocean and killed more than 225,000 people in South Asia.

   It also was the scene on July 4, 1929, at Grand Haven State Park, when killer waves swept 10 people to their deaths on one of the deadliest holidays in West Michigan history.

   The culprit here was not a tsunami, but a seiche (pronounced "saysh"). Created by high winds or squall lines that exert intense downward pressure, seiches can make Lake Michigan slosh back and forth like water in a bathtub, sending powerful waves racing to the shorelines.

   Most Great Lakes seiches are small and go unnoticed, but the phenomenon can trigger huge storm surges and tidal waves that quickly alter Great Lakes water levels.

    "A seiche is a smaller version of a tsunami, with a different cause. A seiche is caused by wind; tsunamis are caused by earthquakes," said David Schwab, a research oceanographer at the National Oceanic and Atmospheric Administration's Great Lakes office in Ann Arbor.

   Tsunamis are born along the borders of the Earth's tectonic plates, where earthquakes and volcanoes are common. Because the Great Lakes are not situated near the edge of a tectonic plate, tsunamis cannot happen here, said Peter Wampler, assistant geology professor at Grand Valley State University.

   Schwab said most Great Lakes seiches only produce subtle changes in lake levels. But given the right weather conditions, a seiche can unleash huge storm surges that endanger human life and coastal structures.

   Seiche is a French word that means "to sway back and forth." To understand how a seiche works, blow on a bowl of soup. The tiny waves hit one side of the bowl and reverberate to the other side.

   A seiche works the same way, but on lakes that span thousands of square miles.

   Though less powerful than tsunamis, seiches can strike quickly and with deadly consequences.

   That's precisely what happened in 1929, when 45,000 people gathered at Grand Haven State Park on Independence Day. An early morning storm spawned a seiche that kicked up large waves; one swept a 16-year-old Grand Rapids girl off the breakwater and into Lake Michigan, where she drowned.

   A second seiche swept across the lake about five hours later, unleashing a wall of water that lashed the Grand Haven beach with 20-foot waves and a powerful undertow that pulled nine more people to their deaths.

   "It was a quick and nasty sea," according to a U.S. Coast Guard captain at the scene who was quoted in The Chronicle the next day. "For a short squall, it was one of the worst I've ever seen. Due to the general high water, there were times when the blue sea rolled over the pier, completely submerging the concrete abutments at times."

   Edward Peters, who operated a bath house at the beach, called the waves "the biggest summer sea I've ever seen."

   Bob Beaton, a longtime Grand Haven resident and surfer, said the scariest thing about seiches is that they can strike when the lake is calm.

   "Some of the deadliest seiche incidents have happened on calm days," said Beaton, who has spent years researching seiches and is a member of the Great Lakes Beach and Pier Safety Task Force.

   Seiches also create fierce rip currents below the surface when the lake level rises and then recedes rapidly. "The waves don't scare me, it's the current that drowns people," Beaton said.

   Schwab said seiches are most common in Lake Erie, which is shallower than the other Great Lakes and is often buffeted by southwest winds that cause water levels to fluctuate wildly at opposite ends of the lake, in Buffalo and Toledo.

   There have been several cases of seiches in Lake Michigan triggering storm surges and tidal waves that drowned swimmers, swept people off piers, damaged shoreline structures and left boats stranded in mud when the sloshing waters receded.

   On July 13, 1938, a seiche caused a massive storm surge that stretched from Holland to Pentwater, according to an article in Hope College's Joint Archives Quarterly.

   Waves triggered by the seiche drowned three people at Holland State Park. It also triggered "freak high waves" that drowned 34-year-old Oscar Thorsen, who was swimming in the lake in Muskegon, and another man canoeing in Lake Michigan near Pentwater.

   A seiche that struck Chicago without warning on a June morning in 1954 increased the lake's water level by 4 feet in just 30 minutes. The rising water was followed by a massive wave, 25 miles wide and as high as 20 feet in some areas, that swept dozens of people off piers. Eight people drowned.

   Schwab said the killer wave bounced off the Michigan coast before pounding Chicago, pushing water in some areas 100 feet inland of some beaches.

   Two years later, a seiche triggered a 10-foot swell in Ludington that sent anglers and beachgoers scrambling for safety. The first swell knocked several anglers off the pier and pushed water 150 feet past the normal water line. The water then receded beyond the water line before a second, larger wave crashed ashore.

   Carol Dewyer, who operated a bait shop near the north breakwater, was quoted at the time as saying the seiche caused pandemonium on the pier and beach.

   "All of a sudden a man said the water was coming in the door of the shop and everyone scrambled for high ground," Dewyer was quoted as saying.

   "I saw one little boy slip off the breakwater and couldn't get his footing. Then some man ran out in the waves and brought him in," Dewyer added. "All those people (on the breakwater) just threw down their poles and bait buckets and scrambled for the bank."

   The storm surge was followed by a squall line that buffeted Ludington with 80 mph winds and heavy rainfall.

   Seiches can slosh back and forth across the Great Lakes for hours, depending on the weather conditions. For that reason, the National Weather Service recommends people use caution when swimming in the Great Lakes or venturing out on piers before or after a squall line passes through.

   The weather service issues seiche warnings when conditions are right for a storm surge on the lakes.

   Beaton, who has surfed the Great Lakes since 1962, said he sees several seiches each year. His most recent encounter with a seiche came while surfing north of the Muskegon breakwater last October.

   "I see evidence of seiches in Lake Michigan pretty often," he said. "They're not big very often, but I've seen the lake go up or down by a foot in a matter of 30 minutes."

   Beaton said listening to weather forecasts is the only way to know if conditions are right for a seiche. He said it's impossible for a lay person to anticipate a seiche by observing the lake or approaching storms.

   "It's like trying to predict an earthquake," he said.

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