Monday, August 29, 2011

This is Worth a Separate Posting

For those that believe there was too much "hype" about Irene (I do not have an opinion, my head was deep in the data and I didn't watch any coverage until landfall Sunday morning), consider these preliminary numbers from the New York Times. These statistics are from 1980 (when full-time high resolution satellite data was first becoming available) to present:

  • Damage?  First estimates are $14 billion; ranking 8th
  • Fatalities? Tied with Fran for 10th with 21, but Irene's are expected to rise. UPDATE: According to the WSJ, 38 fatalities are now reported as of 10pm CDT Monday. As of 9am Tuesday, the death toll stands at 40. Irene is now #4 in terms of fatalities since 1980.
Average the two and you get the 9th 6th worst hurricane in 31 years.  

And, there is this when you are thinking about forecasts of hurricane intensity,

Imagine, for instance, if Irene had been about 20 percent stronger when it hit New York — that it had wind speeds of about 90 miles an hour instead of 75 miles an hour. That doesn’t sound like a huge difference and from a meteorological perspective, and it isn’t.
But from an economic perspective, that may have mattered quite a lot. Some of the scholarly literature suggests that the economic damage resulting from hurricanes is a function of wind speeds raised to the eighth power. I’ll spare you the math: what that means is that hurricane with wind speeds of 90 miles an hour might be as much a 4 or 5 times more destructive as one with wind speeds of 75 miles per hour. So if Irene had been just a bit stronger, we might be talking about economic losses on the order of $55 billion to $70 billion, rather than a “mere” $14 billion.
Because wind power (the wind's destructive force) is not linear, the forecasts showing winds of 95 to 110 mph near the storm's center (that we were forecasting would move inland farther west than shown in this computer model forecast) had the potential to cause major, major damage.

Given that Irene is already the 10th 4th worst in terms of fatalities at Cat. 1 intensity, those stronger winds would have threatened lives to a far greater extent. This was in the back of our minds as we were making those forecasts of Cat. 2 intensity on Thursday. 

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