# 2293
Hurricane Ike may not be the strongest hurricane to waltz across the Gulf of Mexico, but it is one of the largest, and may be pushing a huge wall of water before it towards low-lying communities.
Normally, we rank hurricanes on the Saffir-Simpson scale, based solely on the windspeeds.
Most of the time, this is a pretty good indication of how destructive a hurricane is likely to be. Unfortunately, it is now about 24 hours before Ike is to make landfall, and we still don't know how strong he will be tomorrow morning.
Forecasters believe he may strengthen today, to a CAT 3.
A CAT 2 storm, such as Ike is now (although he may yet intensify), isn't feared quite as much as a CAT 3 or CAT 4 storm. People are less likely to evacuate, or prepare seriously, for a CAT 2 storm.
But categories can be deceiving.
Katrina was probably a weak CAT 3 when she hit east of New Orleans three years ago, but her previous CAT 5 strength, along with her immense size, gave her a storm surge one might only expect to see with a much stronger storm.
Ike is also a huge storm, bigger in girth than Katrina, in fact. And there are fears that Ike could be pushing a storm surge much higher than one would normally expect from a CAT 2 storm.
The bottom line here is a very large swath of destruction is possible along the gulf coast from Texas to Louisiana, even if Ike doesn't intensify beyond a CAT 2 storm.
The lesson here is that scales are useful, but don't always tell the whole story.
If and when the next pandemic approaches, we will be using a scale similar to the Saffir-Simpson scale to quantify the severity of the outbreak.
Future Pandemics will be ranked from Category 1 (mild) to Category 5 (severe) based on the CFR (Case Fatality Ratio) of the virus.
This chart is from comes from the HHS/CDC document: Interim Pre-Pandemic Planning Guidance: Community Strategy For Pandemic Influenza Mitigation In the United States.
Figure A. Pandemic Severity Index
Unlike hurricanes, where we have a lot of experience tracking and measuring, and forecasting - quantifying the strength, speed, and direction of an influenza pandemic has never been done before.
Instead of hurricane reconnaissance aircraft taking constant measurements in the eye of the storm, WHO and CDC officials will be reliant on local surveillance reports coming in from all over the world to determine the pandemic's Category.
The accuracy of their `forecast' will depend on how well information flows from those areas already affected.
As you know, there are some nations that are not as cooperative as we might wish when it comes to sharing this kind of information.
There may also be informational bottlenecks, and delays in processing information, simply due to the the sheer quantity of data being received.
There are other problems as well.
Pandemics are not static events. Like hurricanes, they can fluctuate in strength - often abruptly. In 1918, the first wave (spring) was mild, by October of that year it had morphed into the deadliest pandemic on record.
We also know that the impact of the 1918 pandemic varied widely around the world, with Northern Europe apparently being the most lightly affected, and India and many more tropical countries more heavily affected.
What may be a CAT 2 in one region could be a CAT 5 someplace else.
And what may start out as a CAT 2 pandemic in one region could suddenly, and without warning, jump to a CAT 4 or CAT 5.
Or a CAT 5 outbreak could suddenly weaken to a CAT 2 pandemic.
We have almost zero experience in forecasting such events. There needs to be a good deal of public education about our limitations in predicting the course of a pandemic.
While I like the pandemic scale proffered by the HHS, we won't know how useful it really is until it is tested under real pandemic conditions.
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