Category Three Hurricane Irene has just passed over Abaco Islands in the Northern Bahamas, and is generally affecting the northern Bahamas. Widespread damage is reported. Over the weekend Irene promises to be a very significant weather event in the US. In order to understand the events that will take place between today and early next week, it will be necessary to revisit the concept of "landfall," which we have discussed here in the past.
Here's the deal. "Landfall" is the moment in time when the eye of a hurricane contacts the land, including any barrier island or mainland. "Landfall" is NOT the arrival of a hurricane. Think of it this way. If you are standing in the middle of the street and a semi truck's path intersects with your position, and we measure the location of the truck from its center, some 25 feet or so back from the front bumper, and the truck stops too that this reference point falls short of reaching you by three feet, you are still very much squished by the semi truck. The eye of the hurricane can be thought of at its "center" (even though it is not always in the middle) but a hurricane can be hundreds of miles wide. If hurricane force winds are arbitrarily set at 70 mph and above, then the part of the hurricane that is analogous to the semi truck's front bumper can hit you on land, mess you all up, and move on up the coast without landfall ever happening. In the case of Irene, this zone of 70 mph or greater winds is shown as the darker color on this map, and the tropical storm force winds as the lighter color:
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Here's the deal. "Landfall" is the moment in time when the eye of a hurricane contacts the land, including any barrier island or mainland. "Landfall" is NOT the arrival of a hurricane. Think of it this way. If you are standing in the middle of the street and a semi truck's path intersects with your position, and we measure the location of the truck from its center, some 25 feet or so back from the front bumper, and the truck stops too that this reference point falls short of reaching you by three feet, you are still very much squished by the semi truck. The eye of the hurricane can be thought of at its "center" (even though it is not always in the middle) but a hurricane can be hundreds of miles wide. If hurricane force winds are arbitrarily set at 70 mph and above, then the part of the hurricane that is analogous to the semi truck's front bumper can hit you on land, mess you all up, and move on up the coast without landfall ever happening. In the case of Irene, this zone of 70 mph or greater winds is shown as the darker color on this map, and the tropical storm force winds as the lighter color:
Read the rest of this post... | Read the comments on this post...