STORM-TIDES ON THE LAKES.
The tidal phenomena on the Lakes have attracted considerable attention during the present season. It is well known that there are no regular tides in our great Lakes ; but it is equally true that storm-tides, such as mentioned below, do frequently occur. One of the most singular instances of this kind was witnessed on the 18th day of May, 1855, on both sides of Lake Ontario, and was described as occurring in the following manner on the same day on Lake Huron : —
The Owen Sound Comet says: "In this bay, the water rose about nine feet and immediately fell ten feet below its usual level, so much so that the bottom of the bay was dry enough to allow a man to cross to the Indian village."
The storm at Owen Sound on the day of this phenomenon was very severe. Vessels were broken from their moorings, piers were displaced, and twenty-five houses and barns were unroofed or blown down. Hail stones were picked up measuring from four to five inches in circumference.
A writer in the Chicago Tribune thus explains his theory of Storm- Tides : —
"Having noticed in the Tribune of yesterday an article on the phenomena of the rise and fall of water in the Chicago River and asking explanations, I would beg to contribute what might be considered a rational view
of the phenomena, and also such facts as I possess.
"I attribute the sudden fall and rise of water at this port, and also at other places on the deep lakes, entirely to barometric changes in the atmosphere
immediately over the lakes, and at or near the places where the phenomena are observed. It is well known that the barometer is very feebly affected
by the passage of the tide waves of the atmosphere due to the attraction of the moon, in comparison to the effect produced by the passage of a great
storm. The atmospheric effect of lunar attraction being general, and acting upon the surface of the whole globe, is producing corresponding changes [p. 458] over its whole surface at the same time ; while the effect of the passage of a severe thunder storm, across any portion of our lake -- affecting the barometer from ten to fifteen times more intensely than the Oceanic Tide Cause — would tend to produce a sudden and local tide, corresponding to the intensity of the barometric change in the central track of the storm. The first wave would culminate under the centre of the storm, and travel with it until it struck the shore, or if north or south on Lake Michigan, until its sustaining cause ceased. The fall and rise of water along the shore would be regulated, as in lunar tides, much by the configuration of the shore, and the direction in which the tide waves strike it. At the point where the centre of the storm passed on or off the lake, the change of level would be greatest.
"The small tide waves mentioned yesterday were no doubt caused by the re-action of the great wave along the Chicago River. Such phenomena have been observed on Lake Ontario, only in a much smaller degree than
on Lake Michigan, due most probably to the difference in their size and depth.
"I think that no such phenomena have ever been observed in Lake Erie ; it is too shallow to admit a great tide-wave to generate, although its height at either end is more affected by strong winds from the same cause than the deep lakes.
"Lake Superior, from its vast size and depth, I think would be found to possess this phenomena in a still more remarkable degree than Lake Michigan, if it were more known.
" A few tidal and barometric observations at Calumet, Michigan City, St. Joseph, Kenosha, Milwaukie, Two Rivers, and this place, during thunder storms, would soon lead to the discovery of the true cause of this
anomaly. Who will observe in those places!"
"G. D. Hiscox."
If Mr. Hiscox's observations be correct, there is a plain distinction to be made between Barometric and Wind tides. For instance, Lake Erie is said to be too shallow to permit the generation of the barometric tide, whilst it is notorious that for this
very cause wind-tides reach a greater altitude on it than is known upon the deeper lakes. We think it will be found that
the highest tides have occurred over shoal beaches, and up bays
and sounds, and if so, far less influence should be attributed to
barometric causes in the production of storm-tides than the
above writer feels, disposed to allow.