Tuesday, April 5, 2011

Unmixed Signals

Couple of articles in today's Oregon Live, here and here. I started to write these up earlier but I did something that turned quite a bit of text into a massive blob of html hamburger, and I'm not going to attempt to reconstruct it now. So, short version: The first article is mainly about Oregon coastal communities' preparedness or lack thereof, for large tsunamis, and some of the work underway to become better prepared. It contains the following quote which despite its sobering content is quite funny in its phrasing:
"The shaking will be so strong, you will most likely fall on the ground," said Nathan Wood, a geographer with the U.S. Geological Survey. "That's a sign you know this is not some little tremor. When you can stand up, that is the indication you should head for high land."
Got that? The shaking is the signal you should fall down, and standing up is the signal that you should run for high ground. Another quote highlights a fact about tsunamis that I didn't really comprehend until I'd seen some of the video clips of the 2004 Boxing Day tsunami:
"It's a wall of water," said Witter. "It is a wave, but its wave length is kilometers long. They are so big they produce a sudden rise in ocean level and continue to flow at that level. If you raise sea level by 20 or 30 feet or even higher, where does it have to go? It flows downhill inland. There will be flooding in every place that is low. Where you have bluffs, the waves will hit the bluffs and go back out to sea. If the tsunami is higher than 50 feet, it will top the bluffs that are lower than 50 feet."
The other article is about a "buddy safehouse" program being developed at Cannon Beach- a community that is mostly at lower elevations. A point that I have mentioned in the past, and developed in much more detail in the earlier post I abandoned, is that many- I would say most- Oregon coastal communities are in large part on elevated terraces. There are a few, like Tillamook, Waldport, and Cannon Beach that are largely on dune, estuarine, and/or beach deposits, and which are vulnerable as a whole. But the heart of nearly all our coastal communities is a harbor and port, and even though most of the population and development might be out of inundation risk, these commercial centers are uniformly vulnerable to the inevitable large tsunami that will accompany a great Cascadia quake. And if it occurs during waking and working hours, these vulnerable area will be full of workers and tourists. In many cases, evacuation routes will be obvious and readily accessible, but in other cases, not so much.

As an example, Newport is the town about an hour west of where I sit. The north shore of Yaquina Bay is a narrow strip of flat developed land that rises quickly to the newer parts of town- a person could get to safety in just two or three minutes of brisk walking. The south shore, on the other hand, is broad and low, and is becoming more and more built up. It is the home to The Oregon Coast Aquarium, Oregon State's Hatfield Marine Science Center, the Rogue Brewery, and NOAA's marine operations headquarters is being built there. Where would those people evacuate to? I'm not really sure.

So the point is, if you live or visit the coast of the spectacular Pacific Northwest- and you should: there's only one really bad day out of about 100,000 or so- take a moment to look at your surroundings and ask yourself, "What would I do?" Having even a sketch of a plan is better than none, and though unlikely, could save your life.

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