Saturday, March 12, 2011

Weirdness in the water: Tsunami surge?

I think I was in the middle of a tsunami surge up into the San Diego Bay. This happened yesterday and today. Here's what I experienced.

Yesterday afternoon, I pulled out my raceboard and headed down to my usual workout beach at the south end of the San Diego Bay. The water was it's usual murky green color. I knew that the tide was going low and so I was expecting the water to be running out of the bay from the south end towards the north. I noticed that the water was moving in the correct direction,  but was barely leaving a wake on the lee (north) side of the channel markers (to be expected since we had a small tide change in the afternoon that day). About a half mile into my paddle, as I approached a shoal indicated by additional channel markers I noticed that the water is now leaving a wake on the opposite side of the channel marker. The wake is now on the south side of the marker meaning that water is now rushing into the back of the bay. 

In addition, there are now a set of standing waves, like riffles in a river, where the water rushing in is colliding with the tide going out causing a little set of rapids right over the shoal. That's a new one to me. I've been paddling that area for four years now and have never seen that type of turbulence in that spot. And, now the water has gone from its murky green color to a uniformly brown muddy condition which stretches completely across the bay. 

You can imagine how baffling this was to me- until I started to try to make sense of it. I think I may have experienced a small tsunami surge which pushed water up into the bay. The water then retreated out of the bay causing the muddy turn over. The same thing happened today while I was teaching a group stand up paddle lesson. From the beach, I could see that the water near the shore was clearly moving up into the back of the bay. A few minutes later, as my students were paddling in that direction, our progress was suddenly slowed down- we had to work hard against the current sloshing back in the other direction. And once again, the water color went from a solid green to a muddy brown. 

There was definitely some weirdness in the water- and I was surprised at how quickly my senses picked up on it. I can only imagine that feeling magnified by a million by the pour souls who experienced the real thing in Japan and in the terrible tsunami in Indonesia a couple of years ago. My heart reaches out to them- I hope yours does too.

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