From
http://www.seagrant.wisc.edu/advisory/coastal_engr/flooding/surge.html
The May 1998 seiche on Lake Michigan.
See also
http://www.seagrant.wisc.edu/advisory/coastal_engr/flooding/surgeflood.html
http://www.coastal.udel.edu/faculty/rad/seiche.html
A tsunami-generated seiche in Hilo (HI) harbor following the earthquake in the Aleutian Islands on 1 April 1946.
Tsunamis and seiches
http://www.metrokc.gov/prepare/hiva/tsunami.htm
Good historical discussion
Example --- An eight foot high seiche was generated on Lake Washington to the east of Seattle, WA in 1891 following an earthquake near Port Angeles.
Lake Geneva, Switzerland, wind produced ½ m high, 72 minute period, 110 km. long
Lake Michigan, 1m high seiche in Feb. 1987
See http://sedul.hypermart.net/stats.htm
For history files on floods.
Seiches are floods where storm winds rhythmically drive waters
back and forth, picking up speed, and pressuring areas that block
the water. They are known for breaking artificial dams, and
devastating the areas in the vicinity of the dams, taking the lives
of humans mercilessly. An example of this is when a seiche caused a
dam in Italy to collapse, killing 1800.
Oct. 9, 1963
Italy
Landslide sent wall of
water over Vaiont
Dam on Riave River
About 1,800 lives
lost; Longarone
and surrounding
area wiped out
Good online hydrologic glossary http://www.usbr.gov/cdams/glossary.html
More material on tsunamis
http://www.tsunami.org/faq.htm
http://www-class.unl.edu/geol109/tides.htm
History of oceanography
http://www-class.unl.edu/geol109/history.htm
Rainfall Frequency Atlas Maps
(Central and Eastern U.S.)
These images were scanned from a copy of TECHNICAL PAPER NO. 40
RAINFALL FREQUENCY ATLAS OF THE UNITED STATES
http://www.srh.noaa.gov/lub/wx/precip_freq/precip_index.htm
From Skilling
Tom,
What is a "seiche wave" which I understand can occur in Lake Michigan; and what causes this phenomenon? .
John Mullins, Oak Park Ill.
Dear John,
A seiche (pronounced saysh) is an oscillation of an enclosed body of water (like Lake Michigan) that continues in pendulum-like fashion after the cessation of the force that caused it. In Lake Michigan, that force is a surge of cool air rushing out of a line of thunderstorms moving outheast across the lake at speeds in excess of 50 m.p.h. The cool dense air rushing out of the squall line causes a pressure jump that "pushes" on Lake Michigan sending a slowly building bulge of water toward the southeastern shore. This causes water levels to drop on the Chicago side and rise on the Michiana side. This surge of water then reflects off the Michiana shoreline toward Chicago as a series of reflected waves taking as long as 90 minutes to make the return trip.
Usually these waves are small (less than two feet) but on rare occasion can exceed six or eight feet. On June 26, 1954 a major seiche sent eight Chicago fishermen to their deaths as a 10 foot wall of water suddenly swept across Montrose Harbor washing the unsuspecting men off the pier.
Dear Tom,
One late summer night, my wife and I stood on a dock on Lake Michigan near Michigan City. The water rose--as it would in a saucer being tilted. It was brief and soon receded. We stood on shore hardly believing what we experienced.
Dan LaSuer, Fort Wayne, IN
Dear Dan,
Working from the information provided, it sounds as if you and your wife may have witnessed a seiche (pronounced saysh)—a sudden oscillation (or series of oscillations) in water levels most often brought on by a fast moving line of thunderstorms. Such a wave hit Michigan City on June 26, 1954. At that time, a wall of water six feet high swept against the shoreline, the product of thunderstorms which raced from Wisconsin out over the lake at 55 m.p.h. The air which surges out of such a squall line has an effect like blowing into a cup of coffee—an act which pushes the liquid toward the opposite side of the cup.
Seiches often reach Michigan City near the thunderstorms that produce them, then reflect off that shoreline, returning to Lake Michigan's western shoreline without advance visible warning signs as a series of reflected waves. It takes seiches up to an hour and a half to reach Chicago.
Dear friend,
In the Chicago area we refer to a seiche (pronounced "saysh") as a sudden rise in the level of Lake Michigan along the shoreline. A
seiche can occur when a line of strong thunderstorms approaches southern Lake Michigan from the northwest.
Cool air rushing out immediately ahead of the storm line produces a temporary jump in air pressure. That air pressure surge "pushes"
on Lake Michigan when it arrives at the western shore, depresses the water level slightly and causes the water to move to the southeast
in a very low bulge that is too small to be noticed.
The "bulge" heads southeast, reflects off the concave shore on the other side of the lake, and then on its return here focuses on the
Chicago shoreline. The result at Chicago’s shore is a temporary rise in the level of Lake Michigan by a few inches and on rare
occasions, by several feet.
I remember reading in the Tribune about an interesting Lake Michigan wave which sometimes occurs when a fast moving thunderstorm
crosses the lake. How often does it occur?
You are referring to a "seich" (pronounced saysh)—the product of a gush of air out of a fast southeast moving (50 m.p.h.+) squall line.
Seiches begin as small but extended waves—only several inches high in deep water (and moving 60 to 120 m.p.h.), they grow rapidly in
shallow water to four feet on Lake Michigan’s east shore and up to eight feet on the west shore. The reflected wave which hits Chicago
is insidious because it arrives well after the storm that produced it when the sun is shining.
The rise in lake levels can be dramatic, as on June 6, 1954 when a 10 ft. seiche swept eight Montrose Harbor fishermen to their deaths.
The big seiches are fairly rare—only five since the early 1950’s.
A seiche on Lake Champlain (4 day ?)