Boatnerd Discussion Forum

[quote="ron locke"]Largest wave on L.S. -Roger Blough- down bound off Munsing experienced 40' wave-Nov. 1998- reported to the Marquette T.V. station .[/quote]

If I recall, a rather big deal was made about her arrival in the Soo after running through that storm. Apparently she was the only vessel that braved the weather. An extremely unpleasant trip, I heard.

The largest ocean wave, as distinct from a tsunami, or the wave that hit Lituya Bay, Alaska in 1958 that was caused by a massive landslide, was measured by the USS Ramapo, a US Navy tanker, in the North Pacific in 1933, with a wave height of 112 feet. There have been other extreme waves reliably reported approaching 100 feet in height.

http://www.nap.edu/openbook.php?record_id=11635&page=215

The following site gives a description of what you might expect as the maximum waves on the Great Lakes, with steady high winds over a fetch of 340 miles of water.

http://www.srh.weather.gov/srh/jetstream/ocean/waves.htm

Largest wave on L.S. -Roger Blough- down bound off Munsing experienced 40' wave-Nov. 1998- reported to the Marquette T.V. station .

The largest storm waves can reach around 40 feet after 2 to 3 days of solid wind. The highest wave that was ever recorded was in the Great Storm of 1913 by the J.H. Sheadle at around 80-90 ft ok height because the captain described that the wave was as high as the mast and it destroyed the aft section and blew out the pilothouse windows and almost put an end to her career.

When I sailed on the old Imperial Sarnia, we had waves breaking ten feet over our main deck on Georgian Bay. Since we were lightship coming out Parry Sound, these waves must've been 20 to 25 feet high, trough to crest! They were so bad, my roomy, a guy off ocean ships, couldn't eat!

I was on Lake Michigan during the Great Blizzard/January 1978. We had steady winds out of the north at 75+ mph and the waves were averaging between 25-30ft. We were in ballast and fought our way up the lake from S. Chicago and that gives the wind a good 300 mile stretch to build waves.

I was a Lake Ontario Pilot for 10 years, biggest I saw was about 22 feet. Nasty day.

The waves on the Lakes don't have the depth of water nor the distance to run like they do on the oceans. On the lakes, waves can build for a few hundred miles at most, while on the oceans, they can build for thousands. Also lacking in the Lakes are the strong currents that are found at sea.

Wave height is based on the following variables: wind speed, wind direction of wind speed aka fetch, duration of the wind speed, width of the fetch, and water depth.

There is a chart that estimates a range of possible wave heights when you put all these variables together. I believe it is called the Initial Wind, wave, sea height chart, but I'm not 100% sure on it.

As I understand it there have been waves experienced by vessel crews on Lake Superior which they estimated at over 40'.

I know that great lakes waves are a little bit smaller than ocean waves in general and that they are more closer together. How big can they get? And why can they not get as big as ocean waves?