As Predictors
The geography of the Hebert Boxes is the key to their use as predictors. The boxes are located such that hurricanes have plenty of space to intensify after passing through them, and the prevailing winds tend to push them towards Florida. Conversely, if they pass outside the box they are either too close to land to intensify much, or are far enough away from land that they are more subject to the influences of steering winds and other atmospheric conditions. These tend to either push the hurricane more westward across the Caribbean Sea towards the Dominican Republic, Haiti, Cuba, or into the Gulf of Mexico where they threaten Mexico and the Gulf Coast states, or eastwards causing them to curve outwards over the Atlantic and miss landfall altogether.
While these boxes provide an indication that a hurricane may threaten South Florida, a hurricane does not have to pass through one to strike there, as were the case with the Labor Day Hurricane of 1935 and Hurricane Andrew, though the latter did skirt the edges of the eastern box. Additionally, a hurricane which does pass through a Hebert Box can very easily miss Florida, or indeed any landfall entirely. Hebert himself acknowledged that the boxes are not a guarantee of hurricane landfall either way, but cautions that if a hurricane passes through one, "really, really pay attention. We worry plenty in August and September when one goes through that box, and we have a certain comfort level when one misses the box."
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