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between our steps 09 04 19 doubleSunlight sparkles on rippling water. The bay seems calm this morning. The level surface looks like linen, flat except for the creases that catch the light.

Once the kayak is a little way from shore long waves roll toward me. The crests are more than two meters apart, and the height from trough to crest is at least thirty centimeters. The prow of the boat rises and falls. The kayak tilts a little as the waves come from the north-east as I move north. The depth of each stroke with the paddle changes as I try to catch the same amount of water to keep the boat straight.

Turning back toward home, the wind is in my face. Flags flap from the docks out toward the water.  Gusts make the water swirl. The crests, still rolling toward me raise the prow as they hit. Now I am confused: which way are they going? How is it that they seem to come toward me no matter which direction I travel?

I stop, watch as crests hit the shore, press rocks up and in, then pull them back with a musical rattle.  I can see that they arrive at the shore from the north-east, which means that they are coming from behind my left shoulder. They seem to be moving against the wind.

A part of my mind works out that the waves and I travel at different speeds, and they are coming at an angle so I am always crossing them.  But that does not explain their relation to the wind.

On days when the wind is strong and from the east, powerful waves grow tall, are driven by the wind, pushed by air to pound the land. At other times, the currents seem more complicated.

With the pool on the farm, a frog jumping in caused ripples to spread from the point of entry. The circles slowly spread across the smooth surface, fading back to stillness. Where the ripple touched the uneven shore, they bounced, encountered the next incoming ripple, cancelling some, doubling others.

I remember this phenomenon, vaguely, from ancient physics classes. We would drop a marble in a wave-tank and watch how the waves spread evenly until they encountered the side and bounced back, meeting the incoming waves. I think there was a formula that could predict the resulting pattern, but that math is beyond me now.

What math would be required to explain Georgian Bay?

When a boat passes, the wake can be seen. In the kayak, I judge how fast the boat was going, how strong the wake will be, whether it is augmented by waves, whether I need to turn the prow into the wake so I don't rock too much.

Sometimes, a set of rolling waves comes at me, like the wake of a boat, but there is none I can see. Did a boat pass beyond the horizon? It seems unlikely that the wake would endure that long, but I also didn't feel a gust that could have caused this.

Someone recently told me that a wind from the west will push water from Lake Huron into Georgian Bay, raising the water level here. This person's house is right down on the shore, so the level matters to them, especially this year.  An east wind will push water between Tobermory and Manitoulin out into the lake. That might explain some of the movement I cannot see the cause of.

Another factor is Cape Commodore. My house is well outside the sheltered bay at Owen Sound. Just a couple kilometres north, the land bends and Colpoys Bay begins. Griffeth Island sits just off the Cape. A west wind will blow across Colpoys Bay and hit the island. Water pushed from the west will follow the narrow bay, then encounter the open space beyond Cape Commodore. Will waves spread and bend? Perhaps some bounce off the island, come back to meet water pushed from the west, and as happens in the wave tank, some troughs will be cancelled, some crests doubled.

I guess.

Some mornings, with a light breeze from the south, gentle ripples move north. Occasionally, the water is still as a flat sheet--never glass--with a mist hovering above it. Most of the time, I take a real good look at the complex wave pattern before heading out onto the bay.

Cathy Hird lives on the shore of Georgian Bay.

 

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