Wednesday, December 26, 2012
Riiiiiiggghht!
As Noah says to the Lord in the famous Bill Cosby routine. As I may have mentioned before, I'm a lifelong -- well, since age 13 -- subscriber to Scientific American, which is probably why I'm such a know-it-all, even though they've been assiduously dumbing it down for the past few years.
Anyhow . . .
Michael Dettinger and Lynn Ingram this month tell us that once every couple of hundred years, California has been visited by the real, diluvean deal. Starting on Christmas eve in 1861 it rained not for 40 days and 40 nights, but for 43, after which the Central Valley was "an inland sea 300 miles long and 20 miles wide." Sacramento was 10 feet under. It took 6 months for the water to drain.
The most incredible fact about all that is that I had never heard of it before. Cal was relatively sparsely populated at that time, nevertheless thousands of people died. If that were to happen today . . .
Guess what. It will. They've been able to trace the record of such events in the sediment going back to 1150 or so, and they have convincing evidence of 5 of them. It turns out that great rivers of water vapor form in the atmosphere and west coasts generally are vulnerable to these events. And of course you know the kicker . . .
Global climate change should make them more frequent, by increasing the amount of water vapor in the atmosphere. If you thought Katrina and Sandy were exciting, well now. Words fail. A simulation of a lesser event -- only 23 days of rain -- found that 1.5 million people might need to be evacuated, with total economic costs of $700 billion. Given that nobody's getting 1.5 million people to high ground very quickly, again, well now. You figure it out.
That's why I'm not making any predictions for the New Year. Shit will happen.
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7 comments:
california! we're #1?
the central valley is not really prepared for this, since it hasn't happened in close to forever.
i suppose that some of the flooding could be averted because of water control systems in place now -- there are large and smaller reservoirs serving various distant populations; there are levees; and a large aqueduct shunts water from the sacramento delta to those selfish people with big lawns and swimming pools in southern california.
california has much more often faced droughts; and the huge agricultural interests in the central valley also use a lot of water, even in those drier years. i'd be interested to see if these water control measures are factored in.
but when it rains a lot, no question that local areas can be very affected. and, i tend to forget that there are quite a few cities in the central valley and delta areas. the valley is essentially a very long bowl, flattish in the farmland areas but surrounded by hills -- so there are uphill places to go -- but that could still leave a lot of homes and businesses wet in the event of a major flood.
i would think it possible, in event of potential flooding, to really increase the flow to so cal. there are pumps along the aqueduct, too -- particularly to get the water through the mountain range between the central valley and LA.
excess down there can be diverted to their drainage systems. (for example, the los angeles river is largely dry and used for storm drainage nowadays; much of it is concrete-lined. you've seen movie scenes filmed there.)
As I understand it, the simulation accounted for flood control measures. This event would far exceed anything they are prepared for. We shall see . . .
Cervantes, one of your most interesting posts, thank you. I would hope that with the huge number of cars in California, people could evacuate in the same way that they leave Miami when there are hurricane warnings. However, two individuals who saw the post and have more knowledge of USian behaviour than I do, told me - immediately - that US people would not believe such a thing, and would stay put until it was too late. One of these individuals spent some years in the US living next to Limbaugh-listening fundies, before moving out.
My understanding of the status of US infrastructure is that the main roads, bridges, and dams are well maintained, the rest not. There are going to be washouts and collapses which will cascade and make evacuation during the rain impossible.
Having a 5 day warning is long enough to safely shut down oil refineries, chemical plants, and nuclear power stations. But there are bound to be accidents and leakages and there will be a long term effect on farming and fishing. Oil pipelines will be unusable and will have to be rebuilt. Oil refineries and cement plants may be impossible to restart. There are also chemicals and fuel stored at military bases, but all I know is that there are reports of contamination and rusty barrels.
i really should try to get my hands on that article, to see what it really says.
the central valley really is very long (about 450 miles), with hills either side. the main business is agriculture -- mostly giant corporate farms. so, there could be a lot of crop damage.
there are a number of cities, including the state capitol (sacramento), so there is flooding potential in parts of those cities. but there is higher ground, and major roadways tend to be higher than the floodplain, i think. it is true that there are more remote areas, which potentially could become isolated.
there is some oil and gas, mostly at the southern end, around bakersfield, which should have plenty of time to prepare. i don't think any nuclear.
this setting is not geographically like other places in the US. the closest comparable that i can think of is the great salt lake area.
anyway, for context, here is the interesting wiki piece on the great flood of 1862, when california was but a few years into statehood, and the upper pacific northwest was also really hammered: http://en.wikipedia.org/wiki/Great_Flood_of_1862
my point about the length of The Valley (and also about water control measures) is that -- while there would surely be local flooding with a 40 day rain -- this is a very very large area to fill, and things aren't the same as 1862.
we also have a lot of emergency response measures in place, because of the other and more usual natural disasters in california (fires and earthquakes). yeah, i should read the article...
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