Sloshing Seiches
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When water sloshes around in a bathtub you end up getting a wet floor. Now just imagine what would happen if the water in a lake or a bay sloshed were to slosh around. Hi I'm Dave Thurlow from the Mount Washington Observatory and this is the Weather Notebook.

Such sloshes in lakes are called seiches. It's a good Scrabble word. These things have been observered in lakes, bays and harbors around the world.

One way seiches form is when strong winds push water towards one side of the lake and when the wind relaxes gravity pulls the bulging water back down and creates a wave that heads for the opposite shore. While usually only a foot or so high, seiches in Lake Michigan, for example, have been known to have reached a height of ten feet.

In 1954 a seiche drowned seven unsuspecting people on a Chicago dock.

Lake Erie, which is more shallow than Lake Michigan and is aligned with prevailing winds has seiches that can reach six feet with a sloshing period of about fourteen hours. Flowing back and forth from Buffalo to Toledo until friction and gravity finally smooth them out.

Seiches can also be caused by geological events like earthquakes and landslides. In 1964 seismic waves from a big earthquake in Alaska triggered large seiches in bayous on the US gulf coast.

The sloshing seiches can also be caused by changes in air pressure across big lakes like Lake Superior and we'll hear about that tomorrow right here on the Weather Notebook.

Thanks today to contributing writer David Appell.

Funding for our show comes from Subaru. the beauty of all wheel drive with major support provided by the National Science Foundation.