FW: News Article: 'Seiche' phenomenon hits often, sometimes kills

["Freidhoff, John" <FREIDHJJ@BuffaloState.edu>]

Sorry I missed most of you, but thought this might be interesting to
many of you.

Captain John J. Freidhoff

> Importance:	Low
> 
> 'Seiche' phenomenon hits often, sometimes kills
> 2/01
> 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. 
> Reported by Jeff Alexander, Muskegon Chronicle
> 
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
sci-vessel is hosted by the Great Lakes Information Network:
http://www.great-lakes.net
To unsubscribe from this list: send mail to majordomo@great-lakes.net
with the command 'unsubscribe sci-vessel' in the body of your message. No
quotes or subject line are required.
About : http://www.great-lakes.net/lists/sci-vessel/sci-vessel.info
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *