Now some estimates suggest the death toll from Sidr may reach 10,000. But how is it possible for a cyclone to unleash destruction on such a scale?
To get a better grasp, one need only look at sea surface temperature anomalies in the Bay of Bengal before and after this storm's passage. These images are courtesy of Remote Sensing Systems.
On November 11, when Sidr was spinning up off the Andaman Islands, the Bay of Bengal was characterized by pretty much uniform warm anomalies, shown in red:
But by November 15, as the storm passed by, the Bay of Bengal had become predominantly characterized by cold anomalies, depicted in blue:
The before-and-after difference, to my untrained eye, appears to be an average cooling of something like 1 degree Celsius for almost the entire Bay of Bengal.
And where did this incredible amount of energy removed from the ocean go?
Unfortunately, much of it it got unleashed upon Bangladesh in the form of wind and waves.
Considered in this light, the news of destruction that we are now hearing should not seem so surprising.
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This is a good object lesson in the science (to the extent that we know it) of Cyclone formation and behavior. Thanks for putting this together. Is this what we should expect more of given the most recent IPCC report?
Chris and Sheri, thank you for making it possible to learn of the approaching and now devastating cyclone and how all of us can help the survivors. US and likely world media are becoming near to useless in this information age for those who want to be informed about more than the lives of celebs and pols. Your blog is outdoing mainstream media.
Chris, the SST images remind me of similar images you might have posted following the cyclone that swept over Wake Island earlier ths year. Same blue tail following behind a very powerful system. From these images, no one can argue where cyclones draw their strength and how that intensity will increase with warmer SST.
You might consider doing a stand alone piece on the evidence these images provide.
You are both important players in this sad drama.
Chris,
I think you know that as tropical cyclones pass over warm upper layers of water there is considerable mixing by turbulence of the warm surface water with the cooler water below. This is largely responsible for the after images being considerably cooler that the before images.
I don't think you meant to imply that the majority of the energy of the warm water was transferred into the kinetic energy of the storm as might be deduced from your post.
thanks for the comments, everyone.
Lance is right--a lot of the warm water is being mixed downward. Some of it is also fueling the storm, though.
Thanks for clarifying, and apologies if my post was misleading on this front.
No I would only partially agree about Sidr and the water temps. The water temps are pretty much the same there this time of year as they were last year. Warm but not astronomically so as they were in Katrina where a 3 degree higher bubble of water was directly under the moving storm. Storms get most of their energy from the water without a doubt and fast moving ones pull it up before the water can cool from mixing.
Sidr though was influenced by a high pressure system that spun it up pretty good. Think of two tires in contact with each other, turn one one way the other spins the other. Sidr though wasnt a huge property destroyer unless you were in the property being destroyed. The Deshi's have been told for years to build better housing, get it up out of the flood plains, and above all to evacuate when its imminent. They knew it was coming for a week. In their case though unlike Katrina they didnt have the resources to move the people to a safer place. So you get a 15,000 kill that will likely really be a 20,000 direct storm kill. Give another three weeks and they'll lose another 20,000 from starvation, water, cholera. Unfortunate but nature has for the better part decided that there are too many people on this planet and has taken to swacking them whenever it can.
Ever noted that where the population is low that disasters rarely occur?
Chris,
Thanks for the clarification. While I think you are "pulling" for the side of the debate that argues for an AGW-hurricane connection, I admire the fact that you have tried to keep the science honest and accurate.
M. Randolph Kruger, I know you did not give a lot of thought to:
[Unfortunate but nature has for the better part decided that there are too many people on this planet and has taken to swacking them whenever it can. . ]
because you have the resources to own, borrow or use a computer. So, by comparison with most, if not all of the victims, you are rich.
In this case Nature picked on the very poorest again. It sure helps to be rich when the big storms come roaring in.
The rich don't get swacked as often or as hard.
Give some thought to their economic conditions and don't put the blame on nature.
Every year, dozens of intense tropical cyclones spend days pounding low-population stretches of ocean with 100 kt winds, and, surprise surprise, it isn't called a disaster because no-one lives there! Remarkable, isn't, Mr. Randolph Kruger?
M. Randolph Kruger, ever heard of "global warming"? do you know who got noble peace prize this year? I guess no. We live in a delta. The last two times we had this kind of major cyclones were in 1970 and 1991. But now we can feel that climate is changing rapidly. we have two major flood this year which never happened before. And after that this cyclone SIDR. Almost 90% of our land is higher than the sealevel by 1/2 meters. So, surge of 3-5 meter high will cause enormous damage. Rich people's use SUV for their luxury and we those live in delta are paying the price. and if there are too many people in the world, why do poors have to suffer all the time? First get your concept right about global warming, it's effects then write about cyclones. When we were born, life was beautiful. but now for some stupids we are facing the wrath of nature more than others....