Why is landfall marked and counted down to when the eye of the hurricane hits, when it seems all the damaging parts are not the eye at all?
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The strongest winds don’t generally stretch that far from the eye (20-50 miles generally, depending on lots of factors), so “landfall” is usually referred to when the outer edge of the strongest bands of wind reach shore.
It’s a definable, somewhat-definite part of a hurricane. Which part other than that should we pick to track where the hurricane is as a point on a map? The kinda-sorta side that’s rotating and growing/shrinky constantly is hard to track… and where is that exactly? When you’re near the approaching hurricane and it’s clouds as far as the eye can see, and in one direction it just gets more windy and rainy: where does the surrounding stop and the hurricane start?
Couple reasons. The first is that there’s no other good reference for when the storm is “touching” land. Clouds and rain get flung off from the storm and can start hitting the land many hours or days before the rest of it hits. The eye wall is at least a well-defined mark to use to define the storm.
The other big reason is that landfall almost always causes the storm to weaken and usually signals the beginning of the end of the storm. Hurricanes are fueled by warm, moist air coming from the ocean. Once the eye goes over land, that fuel is disrupted. Plus, there’s a lot more stuff getting in the way of the wind, slowing it down and further disrupting the strength of the storm. So, landfall is a significant event in the evolution of the storm.
Once you get into the eye of the hurricane you’re in a weird calm zone. I’ve heard stories of people going outside and having blue skies above them, while all around are walls of clouds. The winds in the eye wall are definitely the most damaging winds of a hurricane. The difference between the eye and the eye wall couldn’t be more pronounced.
yeah that’s super interesting. the eye is calm but the bad stuff is in the rainbands. they just like to hype up the event to keep us alert I guess
The eye is the center, and that’s where warm air rises up and cools to generate rain for the storm. Once that is over land, there is far less water entering the storm, and therefore, the storm starts decreasing in power.
A hurricane can hit Florida, make landfall there, and then continue over the Gulf of Mexico, gaining power and make landfall in Texas as a much more powerful storm. That same storm can hit Georgia, but then be dead by the time it reaches Mississippi
The eye is also pretty easy to see and predict, where as the outer edges of the storm vary a lot
It’s just the convention that has been agreed upon. Landfall is marked when the middle of the eye reaches land. Many times, hurricanes are irregularly shaped, so using the center of the eye is usually an easily defined point. Also, there is some judgment as to when and where landfall is marked.
The landfall estimate is for the center of the hurricane’s eye. Why the center? Because that’s where the pressure is the lowest, which produces the highest storm surge (the intense low pressure literally pulls up the base line level of water, so now “sea level” is normal sea level plus 5-20 feet). This is also surrounded by the strongest winds, which, when paired with the storm surge, is the source of the most damage.
Think of the hurricane as a spinning top, and the eye is the point that it spins on.
If you spin a top on a table and there is playing card laying on that table, at what point do you consider the top to be “on the card”? When the big spinny bulbous part is overlapping it? Nope, it’s not officially “on the card” until the tip that the top spins on is actually on the card.
That’s the same logic for landfall. “When is the hurricane officially on land, and not on the water?”
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