Published: 2008-09-13 10:10:30
Updated: 2008-09-13 10:10:30
Posted September 13, 2008
MIKE MOSS SAYS: Anna, Near the eyewall of a hurricane, where winds are typically strongest, the highest wind speeds on average are around half a kilometer (1600 feet) above the surface and decrease from there both with greater altitude and toward lower altitude. The attached graph is from a National Hurricane Center publication, and shows the vertical shape of the average wind profile obtained by dropsonde measurements. This shows that winds near the eyewall (in red) tend to increase rapidly from the surface up to around 500 meters, then decrease slowly up through 3,000 meters (around 10,000 feet). The blue line is for wind measurements outside the eyewall where wind speeds tend to be somewhat lower. In this part of the storm, the strongest winds tend to occur a little higher up, around 800 meters (about 3,000 feet).
Because of this distribution of wind speed, damage can be surprisingly great at times many floors above the ground when hurricanes move ashore in areas that include some high-rise buildings. It's also worth mentioning that while the curves on the attached graph are a reasonable average, the profile at any one time on any single storm can vary quite a bit from this shape.