This is hurricane durian on September 1st, 2019 and
Here it is more than 24 hours later still pummeling those same islands
you see
Hurricane durian. It's stalled right there in its path
In fact at times it was crawling across the Bahamas at just one point six kilometers per hour
That's slower than the average person walks
So what causes hurricanes like durian to stall and why does it matter?
First of all, durian is not the first hurricane to stall not even close actually in
2018 for example hurricane Florence spent more than 50 hours within one small region of North Carolina and the year before
Harvey, lingered over the houston area for more than two days straight, but in every case
Hurricanes, that stall are really bad news
Because the longer they linger the more rain they unload and the more damage they deal
Harvey for example dropped more than sixty inches of rain in some parts of Texas and it cost the country an estimated
125 billion dollars
doreen on the other hand dropped more than 36 inches of rain in some regions and is expected to have a
multi-billion dollar price tag as well
So then why - hurricane stall in the first place think of a hurricane like a cork bobbing in a stream although it produces
Its own wind and spin it actually travels. Thanks to larger wind patterns
Which carry it along those wind patterns themselves evolve and change and sometimes
The winds that guide to hurricanes collapse endures what you might think of as a stagnation point. That's Tim Hall
I'm a senior scientist at NASA's Goddard Institute for Space Studies in New York
And he says that at these stagnation points a hurricane has nowhere to go
So it just sits there
Dropping rain until another wind system picks it up and pushes it along and that's exactly what happened in the Bahamas
When Dorian arrived a pressure system nearby called the North Atlantic
subtropical ridge started to weaken and
That caused winds that were carrying the hurricane to essentially stopped blowing and it will definitely happen again
in fact those stagnation events
They're actually becoming more common and as a result, so are hurricanes that stall
according to Hall's research there were 66 hurricanes that stalled in the North Atlantic between 1944 and
2017 and nearly half occurred in the last third of that time frame
Which helps explain another trend the average speed of hurricanes in a given year is declining
in fact compared to the mid 20th century
Hurricanes today are moving on average about 17% slower
Scientists still aren't sure why but we've got some suspects and the suspects are that in a warming climate
climate model simulations show both in the future and in the past several decades
a
reduction in the overall
tropical wind patterns and
Unfortunately a stalled hurricane isn't the only consequence of climate change
It's also been shown to worsen storm surge increased rainfall and produce more intense storms
So while durian is of course devastating, it's likely just one of many hurricanes like it still to come
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