As a meteorologist, Hurricane Ian is the nightmare storm I worry about most

This is the kind of storm that destroys a community forever.

Read the whole story

 

[pokrface]

I live in houston and spacecityweather.com has been my goto resource for weather for years. I have also been reading Ars for years.


I just finally put two and two together about the author, it is kind of embarrassing.

You want your noodle really baked? I run the Space City Weather backend.

 

[pokrface]

directly quoting from the article:

As a forecaster you worry about three primary threats from hurricanes—strong winds, storm surge, and inland rainfall.

Well yes. But my question is, why is this particular hurricane somehow different in these threat assessments to the essentially yearly hits that Florida takes? Why would the storm surge be worse? Why would the rainfall be worse?

Why is this particular storm exceptional, and of particular interest to me is whether these exceptions are part of any evolving patterns, or just freak bad luck? Because meteorologists have started calling "once in a several-century storms" EVERY YEAR for like the last half decade. So either their models aren't very good at statistics (unlikely) or something not included in standard models is changing, and so what (specifically, not just generically global warming) is changing about these storms that is making this the new normal?

In no particular order: the rainfall is going to be worse because the storm lacks steering currents, so rather than zipping through, it's going to do a mini-Harvey and move very slowly along its track. The slower it moves, the more rainfall it dumps.

Storm surge is driven primarily by wind, and geography plays a role. Tropical cyclones rotate counterclockwise, and so they have a "good side" and a "bad side"—the part that sweeps in from the water drags more surge in with it. With Ian, the "bad side" is the southern-ish side of the storm, as the counterclockwise circulation pulls water along over land. The area with the 12-16ft forecasted surge is on the "bad side" and is the recipient of bad luck and strong winds.

The cyclone's winds themselves are a function of lots of things, including how much wind shear exists along the thing's path, because wind shear helps slow down cyclone organization. But the major factor that drives the winds is the heat of the water, and the gulf in September is basically the temperature of a warm bathtub. This can help trigger an effect called rapid intensification, which is IIRC what Ian has gone through.

So, the rainfall/wind/storm surge factors are interlinked, but require lots of bad luck to all be severe at the same time. In most cases, either there's an intensity falloff in winds that damps down the surge as the thing tracks toward land, or the track itself turns out to be aimed such that the nearest population centers aren't on the "bad" side of the storm.

And, finally, yes, climate change is contributing to the increasing intensity of tropical cyclones.

 

[pokrface]

Hey Lee: Next time we want a live report from you or Berger…on-site.

As a veteran of more than a dozen of these awful things: not a fucking chance. I'm the first one evacuating when a hurricane heads toward H-town. And I'm counting the minutes until i can move away from the gulf coast and never come back.

 

[pokrface]

There are a few homes built in disused ICBM silos

An underground home is not the place I'd want to be during a hurricane. The winds are bad, but the storm surge + flooding are typically far more destructive. You better hope you still have the original government-provided generators and pumps to keep that former silo from filling up with water when you're sitting underneath 10 feet of storm surge.

(Also, this is one of the reasons why the USG didn't emplace any ICBM silos on the coasts...)

 

[pokrface]

People trying to evacuate Houston before Rita:

I sat through that evacuation. Took us about 22 hours to travel 80 miles. Definitely an experience I would not like to ever repeat again.