The ability of hurricanes to shape continents

I remember hearing after Hurricane Harvey in 2017 that 275 trillion tons of water was displaced from the ocean and deposited onto the land. There was some poppy research demonstrating that this weight actually modified the elevation of the state of Texas by a few centimeters. Other hurricanes may also trigger earthquakes [1]. Another common feature is beach erosion.

With the track of the latest one, it is unmistakable that the movement mirrors the eastern seaboard, and several in recent years have had very similar tracks where they nestle in off the coast of Florida/Georgia and then move Northeast. While the pre-historic frequency of hurricanes isn't known, they've probably been hitting that spot at a regular clip for a looooong time.

Given that hundreds of thousands (and possibly millions) of hurricanes have hit North America, is it reasonable (or dumb) to suggest that the shape of the continent was determined over the years by the movements of hurricanes?

[1] https://www.nature.com/news/hurricane-may-have-triggered-earthquake-aftershocks-1.12839

@wildgrass
My guess is the plate movements, like in the case of the America's, the split from the time when the America's and Africa were joined together and the resultant pulling apart would have and is a much larger effect than anything hurricanes could do, I imagine it would be more like someone making a 3 dimensional art project and a 3 yo kid at work with a small hammer on the work, unable to make really major changes to the work as a whole.
That said, I can see each hurricane doing it's little bit like you said, dumping trillions of tons of water on land.
One question about that particular dump in Texas, would that water have been highly saline, like pure ocean water or would it have been more like rain with whatever saline level ordinary rain contains? If it was saline there may be other consequences like effecting crops on farms.

@sonhouse said
@wildgrass
My guess is the plate movements, like in the case of the America's, the split from the time when the America's and Africa were joined together and the resultant pulling apart would have and is a much larger effect than anything hurricanes could do, I imagine it would be more like someone making a 3 dimensional art project and a 3 yo kid at work with a small hamme ...[text shortened]... nary rain contains? If it was saline there may be other consequences like effecting crops on farms.

The rain water was not saline. It evaporated out of the Gulf of Mexico into the hurricane.

Combined with hurricane-related soil erosion (and time) it probably has done a lot. Uncanny how similar the tracks are to the land masses in the southeast. But I suppose the land could also be directing the hurricane tracks?

@wildgrass

Yeah, that was obvious by the way for instance, Dorian just happen to have stalled over the Bahama's, the images they showed had the eye of Dorian hanging around that one island for nearly 2 days and of course causing more destruction then ever seen before in the Bahama's. So when Dorian ran its fringes into Florida, it was clear, to me at least, there was interaction between the coast and the hurricane to both steer it and absorb some of the energy associated with Dorian.

It was clear to me, unless I was totally not seeing it, when the fringe of Dorian hit the US, the land introduced a significant amount drag on the winds which would have introduced a torque effect on the whole hurricane and that torque would steer the hurricane away from the coast at least while it was just the fringes of the 'cane hitting the coast.
If it was destined for the eye to be a lot closer to the coast I imagine the steering effect would have been reduced and the drag effect of it going on land would have increased a lot and slowing down the intensity where it could not maintain a cat 5 or 4 status for long, the drag against the ground saw to that.

@sonhouse said
@wildgrass

It was clear to me, unless I was totally not seeing it, when the fringe of Dorian hit the US, the land introduced a significant amount drag on the winds which would have introduced a torque effect on the whole hurricane and that torque would steer the hurricane away from the coast at least while it was just the fringes of the 'cane hitting the coast.

is this a known property of hurricanes? From the coverage I saw, they explained that the hurricane was being steered by the other weather systems in the area, not the land masses themselves.

@wildgrass
The explanation I heard was about a high pressure area centered somewhere around Bermuda and that high pressure system pushes on the hurricane to steer it when it was out to sea and that could if severe enough definitely would steer the hurricane into the land mass but still, the land mass itself absorbs wind energy a lot stronger than being isolated out in the ocean.
We here in Pennsylvania have had very few hurricanes hit in our area, Pocono mountains and such because by the time the hurricane creeps up the coast inland it loses much of its wind energy from trees, land masses, large buildings and the like that clearly take a toll on the total wind energy of the hurricane.
But the steering still comes from the high pressure zone centered around Bermuda and the bigger that system of high pressure the more of a wall and push on the hurricane steers it inland or a lesser high pressure system is not strong enough and the 'cane hangs a right and goes out to sea and misses land altogether, but even the fringe of the hurricane can cause flooding close to the coast.

@sonhouse said
@wildgrass
The explanation I heard was about a high pressure area centered somewhere around Bermuda and that high pressure system pushes on the hurricane to steer it when it was out to sea and that could if severe enough definitely would steer the hurricane into the land mass but still, the land mass itself absorbs wind energy a lot stronger than being isolated out in the o ...[text shortened]... misses land altogether, but even the fringe of the hurricane can cause flooding close to the coast.

RIght. 20-ish of these very powerful storms form every year aimed at the US east coast. It seems that if every hurricane is taking a dozen feet of oceanfront off the coast of Florida they have substantially shaped the continent. If Africa's horn didnt produce so many hurricanes, how different would N. America look?

@wildgrass
My brother in law has a condo in West Palm beach and I remember going there like 15 odd years ago and the condo had a nice boat landing and was set back a ways from the beach.
Went back a couple of years ago and the beach looked like it had been dynamited.
The boat landing, concrete roadway, was in two pieces, the broken piece with a drop off of about 2 feet and the beach itself was a LOT closer to the condo than the first time I was there.
A striking difference. Clear erosion and that could not have happened by the power of just normal rainstorms. It was clearly from past hurricanes.

@sonhouse said
@wildgrass
My brother in law has a condo in West Palm beach and I remember going there like 15 odd years ago and the condo had a nice boat landing and was set back a ways from the beach.
Went back a couple of years ago and the beach looked like it had been dynamited.
The boat landing, concrete roadway, was in two pieces, the broken piece with a drop off of about 2 feet an ...[text shortened]... could not have happened by the power of just normal rainstorms. It was clearly from past hurricanes.

That's one generation. Now extrapolate back 15 million years. It must be a hundred miles?

@wildgrass
I wonder if that has actually been quantified?
I found this link, but it seems to be about present erosion, based on Lidar and they said Lidar can only penetrate water to 4 meters depth. So there is nothing about the deep past in this link.

https://www.sciencedirect.com/topics/earth-and-planetary-sciences/beach-erosion

This link shows erosion from tsunami's, but only back 900 years, no study of hurricane damage to beaches.

https://phys.org/news/2017-09-geologists-breadth-depth-erosion-ancient.html

My guess is such beach erosion would be covered up like ancient meteorite craters are covered by millions of years of weathering.

@sonhouse

It'd be interesting to see a model of what North America would look like if Atlantic hurricanes didn't exist.