Frances has passed into the Hebert Box. What's the Hebert Box?
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If it's in the square, beware.
It's called the Hebert Square. Almost every Atlantic storm that has struck Southeast Florida as a major hurricane has gone through this small box in the ocean, and almost every major storm, of at least 111 mph, that has bypassed it has missed South Florida.
The box was "discovered" a quarter century ago by Paul Hebert, a three-decade veteran of the National Weather Service and National Hurricane Center in South Florida and now a weather consultant for Florida Power & Light Co.
Hebert also has a second box. This one's in the western Caribbean Sea, where late-season "back door storms" historically form, then cross Florida from the south or the west and hit Southeast Florida coastal counties from behind. Every storm that formed in the western Caribbean and later struck peninsular Florida as a major hurricane went through Box 2.
Many storms that went through the two boxes did not hit Southeast Florida. But, he said, "We want people to get all excited when a storm goes through the box. You'd better pay attention. They have plenty of time to become major hurricanes."
Hebert (pronounced AY-behr) says statistics alone would suggest the big storms come through his boxes.
"Why wouldn't they?" Hebert said. "They come up Hurricane Alley from the east and they come up from the south."
But there are also meteorological factors, he said.
"Coming from the southeast, if they go north of the box (Box 1), they're already so high up that it's very easy for the approaching low pressure areas to turn them before they approach South Florida." And, he said, many a powerful storm that passed through the box steered north of Hispaniola, the island shared by Haiti and the Dominican Republic, or Cuba, and stayed strong and deadly all the way to South Florida.
Those that came in south of the box passed over those islands, and mountains tore up their circulation like a pencil stuck through the spokes of a bicycle. So far, Hebert said, none restrengthened to a major hurricane by the time it struck Southeast Florida. David, for example, was a strong Category 4 when it leveled the Dominican Republic, but was only a Category 2 when it skimmed Palm Beach County.
And, Hebert said, "If a storm forms in the western Caribbean, odds are better that it will go through the box (Box 2)."
In August and September, most storms that pass through that box end up going west and north and striking Texas and Louisiana. Irene, in October 1999, went through Box 2, and though only a strong tropical storm in Palm Beach County, it did manage to dump about a foot and a half of rain on the area.
Hebert said that although people can use the boxes to become aware of pending storms, they shouldn't be lulled into ignoring those that don't pass through. Any statistic is only good as the one exception, and some storms didn't go through either box because they formed at a point where they were already past them.
In 1935, a system formed in the Atlantic, west of Hebert's Box 1, and grew in 36 hours from a tropical storm to striking the Florida Keys as the most powerful hurricane on record. The "Labor Day Storm" killed more than 600 and washed Henry Flagler's Key West railroad into the sea.
"Despite our advances in technology," Palm Beach County Emergency Management Director Bill O'Brien said, "We can be surprised by a really vicious storm that never goes through the Hebert boxes, and doesn't always give you any warning.
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