steve crisp's blog

the ignorance is amazing

 abuse

WRAL currently has a news story regarding Hurricane Hanna complete with user-generated comments. Some of those comments are the most ignorant things I have ever read. You know, if you want to make stupid political statements regarding the presidential race, that is your choice. But when you start messing with a situation where people can get killed if they listen to your idiocy, that is an entirely different issue. Here are some of the things I have read:

One poster is claiming that there is nothing to Hanna since there are no watches or warnings posted yet. They obviously have no clue what hurricane watches and warnings are.

A hurricane watch is issued when hurricane conditions are possible within 36 hours of the watch being issued. A hurricane warning is issued when a hurricane is anticipated to strike a given area within 24 hours. Warnings may be issued for conditions where the wind does not reach a sustained hurricane force, but where other conditions such as storm surge or high waves may threaten property or lives.  Given that we are more than 48 hours from anticipated landfall, the criteria have not been met to issue watches or warnings for the North Carolina coast.

The National Hurricane Center may issue from time to time a hurricane advisory if there is an increased probability for a hurricane strike, but the timeframe or uncertainty is outside of a formal watch or warning. We are currently under such an advisory which is updated every six hours.

Another poster has derided the coverage of the storm, and especially the comparison to Fran. The poster claims that the conditions are completely different in that with Fran the ground was saturated and the storm was a category 3 at landfall. Well, perhaps she has forgotten Fay and all the rain that dumped on us. The ground is rather juicy at this point. And while Hanna may not be a cat 3 at landfall, its forward motion will be greater than Fran's was so it will not have time to lose strength as it moves inland. That rapid forward motion also adds to the wind speed in the circulation itself, increasing the speed of the wind at any point to the east of the eye. She also had the audacity to compare her experiences in Charleston SC with conditions in Raleigh.

Not only are construction techniques in the Charleston area completely different than in central NC, but the trees are different as well. Charleston has a code requiring reinforced buildings; Raleigh does not. A structure in Charleston that could easily survive a cat 3 storm does not exist here. Cat 1 conditions here can tear apart a house especially with the threat of imbedded tornadoes. And the trees...

Coastal trees are adapted to bend under high wind. Inland trees, full of leafs and with different root systems, come down hard on structures in winds that a coastal tree would laugh at if trees could laugh. There is a major difference between how a palm or magnolia responds to wind and the response of an oak or pine or sweetgum.

Finally, some posters are claiming that since the National Hurricane Center has pulled the expected track of Hanna to the east that Raleigh is out of the woods. I can not emphesis this point enough -- the center track on the projected path of the NHC charts has no more probability of a strike than the entire bubble surrounding it. At any given latitude within that cone of motion, there is an equal probability that the eye of the storm will pass over a specific location. That the track has shifted to the east simply means that areas to the west are no longer expected to have the possibility of experiencing hurricane force winds while areas to the east which formerly were not in the cone now have a chance of seeing a hurricane.

Further, just as the track has shifted east slightly, it can just as easily shift back to the west if the guiding winds change or the high pressure system to our north strengthens a bit. If your location is within the cone, prepare to be hit by a hurricane until your location has moved out of the cone significantly with subsequent forecasts especially as we get closer to landfall.

There are two significant issues involved with predictions regarding Hanna that are not seen with many hurricanes. And they are greatly complicating the forecast.

1. The storm is coming parallel to the coast rather than at a greater angle, coming straight in. When a hurricane is running parallel to the coastline, small variations in motion can lead to huge differences in projected landfall locations.

2. The storm is projected not only to turn north and head up the coast from Florida to North Carolina, but there is an additional turn to the northeast projected. The timing and angle of that turn can make a huge difference in the ultimate track of the eye. If the turn occurs south of us, the storm passes over NC at the coast or even possibly out at sea. If the turn is delayed, or does not happen at all, the storm passed over central or even western North Carolina.

There is no way to accurately predict the timing or angle of that turn at this point beyond what models may indicate. And the farther out in time from the present you are, the greater the error rate of the models.

The bottom line is that if you do not know what you are talking about, keep your mouth shut when it comes to advising people what to do as a hurricane is approaching.

If you are interested, I would invite you to look at my blog from 12 hours ago regarding Hanna. There are a lot of good comments from a bunch of folks regarding hurricane preparation.