New promise of forecasting meteotsunamis
Photographer's images aid research of rare Great Lakes wave

Date:
April 1, 2021
Source:
NOAA Headquarters
Summary:
On the afternoon of April 13, 2018, a large wave of water surged
across Lake Michigan and flooded the shores of the picturesque
beach town of Ludington, Michigan, damaging homes and boat docks,
and flooding intake pipes. Thanks to a local citizen's photos
and other data, scientists reconstructed the event in models and
determined this was the first ever documented meteotsunami in the
Great Lakes caused by an atmospheric inertia-gravity wave.



FULL STORY ==========================================================================
On the afternoon of April 13, 2018, a large wave of water surged across
Lake Michigan and flooded the shores of the picturesque beach town
of Ludington, Michigan, damaging homes and boat docks, and flooding
intake pipes. Thanks to a local citizen's photos and other data, NOAA scientists reconstructed the event in models and determined this was
the first ever documented meteotsunami in the Great Lakes caused by an atmospheric inertia-gravity wave.


==========================================================================
An atmospheric inertia-gravity wave is a wave of air that can run from 6
to 60 miles long that is created when a mass of stable air is displaced by
an air mass with significantly different pressure. This sets in motion a
wave of air with rising and falling pressure that can influence the water below, as it synchronizes with water movement on the lake's surface like
two singers harmonizing.

"That meteotsunami was hands down off the chart awesome," said Debbie
Maglothin of Ludington who took photos of the event. "The water in
between the breakwaters didn't go down like the water on the outside of
them, so it created waterfalls that cascaded over the breakwaters. Had
this event occurred during summer it could have washed people right off
the breakwaters." Meteotsunamis generated from this type atmospheric
condition are common around the globe, but in the Great Lakes, the
few well documented meteotsunamis have been driven by sudden severe thunderstorms where both winds and air pressure changes have played
significant roles.

Combining water and weather models While there are currently no forecast
models that effectively predict meteotsunamis in the U.S., new NOAA
research based on the Ludington wave demonstrates that existing NOAA
numerical weather prediction models and hydrodynamic forecast models
may enable scientists to predict these meteotsunami-driving atmospheric
waves minutes to hours in advance. The research is published in a special edition of the journal Natural Hazards about meteotsunamis.



==========================================================================
"The good news with this type of meteotsunami is that it is easier to
predict than ones triggered by thunderstorms," said Eric Anderson, an oceanographer at NOAA's Great Lakes Environmental Research Laboratory
and lead author of the study. "Our short-range weather models can pick up
these atmospheric pressure waves, whereas predicting thunderstorms is more difficult." Meteotsunamis are a lesser known category of tsunami. Unlike
the more well known tsunami -- such as the catastrophic 2004 Boxing Day
tsunami in Indonesia, which was caused by an earthquake on the seafloor, meteotsunamis are caused by weather, in particular some combination of
changing air pressure, strong winds and thunderstorm activity.

"Because the lakes are relatively small, meteotsunamis typically need more
than a jump in air pressure to drive them," said Anderson. "That's where
the thunderstorms and wind come in to give them a push." Great Lakes
have history of meteotsunamis Meteotsunamis occur around the world,
and are known to occur in the United States primarily on the Great Lakes
and along the East and Gulf of Mexico coasts. Meteotsunami waves in the
Great Lakes can be particularly insidious because they can bounce off
the shoreline and come back again when the skies are clear. They are
relatively rare and typically small, the largest producing three to six
foot waves, which only occur about once every 10 years.

Predicting these waves in advance would give communities potentially
life- saving warnings and would allow residents and businesses to take
measures to better protect property. The Ludington meteotsunami resulted
in some property damage but no serious injuries. Had the meteotsunami
struck in the summer when swimmers, anglers and vacationers flock to
the lakeshore beaches, parks and waters, it might have been a different
story, as was the case with a meteotsunami that took the lives of eight
people in Chicago in June 1954.

"It's a gap in our forecasting," said Anderson. "With this study and other research we are getting closer to being able to predict them in advance." ========================================================================== Story Source: Materials provided by NOAA_Headquarters. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Eric J. Anderson, Greg E. Mann. A high-amplitude atmospheric
inertia-
gravity wave-induced meteotsunami in Lake Michigan. Natural Hazards,
2020; 106 (2): 1489 DOI: 10.1007/s11069-020-04195-2 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/04/210401151245.htm

--- up 1 week, 8 hours, 39 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1337:3/111)