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Originally Posted by NeilBlanchard
Downtown Memphis Tennessee was under 10 or 15 feet of water. Oklahoma got severe floods, as did Wisconsin and Michigan; along with many more tornadoes than are usual. While I was at the X-Prize in June, there were many tornadoes all around during that weeks and before and after.
And yes, places like Pakistan and Vietnam get 30+ inches of rain in a few days. The Pakistan flood was about one years of rain (in an average year) in a few days. One fifth of the country is utterly devastated, with virtually every bridge, road and building destroyed, in the affected areas. About 20 million people are homeless. Entire crops were wiped out, and they will not be able to plant those lands for at least several years.
Have you ever heard of such a thing before?
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Before I would consider a flood "unusual", I would first have to see if it extended beyond the flood plain into the hillier areas surrounding the plain. The problem is people like to build and grow crops on flat land and in hilly regions the only flat land lies next to rivers and creeks. This land is flat because it floods occasionally, depositing rich sediments that is the reason that it is flat and so fertile. It may not flood every year or even every 100 years, but that flat land next to the river eventually will be underwater as the river deposits yet another layer of sediment on the flood plain to make it flat. All of the photos I've seen of the Memphis, Nashville, and Pakistan flooding (and of the big Mississippi floods back in the 1990's) all showed flat land underwater, which meant that the river had just swollen to cover its floodplains. It may have been a 1000 year flood, but if that flood was limited to the floodplains, then it is nothing unusual and well within the usual vagaries of the climate for that region if you are looking at more than just a few decades of climate.
The current crop might have been wiped out, but I don't see why they wouldn't be able to replant to winter crops as soon once the land dries out as they enter their fall dry season. And the land will be richer thanks to the new layer of sediment just deposited. After all, in Egypt before the Aswan Dam was built, the Nile would flood like clockwork every summer and the people would plant their crops on the newly en-richened soils each fall. The reason this flood hit the Pakistanis so hard was that it is a fairly dry region dependent on irrigation from the Indus, so the bulk of their towns and fields lie within the Indus floodplain.
One reason we seem to have more tornadoes than in the past is that many tornadoes used to appear in lightly populated rural areas where no one would see them and their damage was not noticed. Today, thanks to suburban sprawl, many of those formerly lightly populated areas are now covered with housing and the appearance of a tornado is seen by many eyes and damage they cause reported to many insurance companies. And any tornadoes not spotted by humans are captured and counted by Doppler radar, so every one is counted, which wasn't the case as recently as the 1960's.
I don't consider tree rings to be a good indicator of climate since the tree's annual growth rate is responding to many different factors including spring/summer temperatures, winter/spring/summer rainfall, late spring frosts, insect feeding, and herbivore feeding pressure. How can you know many thousands of years later which of these factors accounted for a good or poor ring growth year?