Hurricanes Are Moving More Slowly, Which Means More Damage (npr.org)

An anonymous reader shares a report: Hurricanes are moving more slowly over both land and water, and that's bad news for communities in their path. In the past 70 years, tropical cyclones around the world have slowed down 10 percent, and in some regions of the world, the change has been even more significant, according to a study published Wednesday in the journal Nature. That means storms are spending more time hanging out, battering buildings with wind and dropping more rain. "The slowdown over land is what's really going to effect people," says James Kossin, the author of the study and a tropical cyclone specialist at the National Oceanic and Atmospheric Administration. He points to Hurricane Harvey's effect on Houston as an example of what slower storms can mean for cities. "Hurricane Harvey last year was a real outlier in terms of the amount of rain it dropped," he explains. "And the amount of rain it dropped was due, almost entirely, to the fact that it moved so slowly."

Comments

More time to get out of the way?

[Oswald McWeany]

More damage where they hit, but doesn't that also mean you have more time to evacuate people to get out of the path. In theory a slower moving hurricane may mean more damage but should it not mean less human fatalities? At least in places that have the financial ability to move people out the path.

Re:More time to get out of the way?

[sqorbit]

I don't know if it was just because I paid more attention, but last Hurricane season they seemed to have trouble predicting the path. They had 3 or 4 probable paths listed at once with at least one. More time should allow for that as long as we can predict where it's going to hit.

Re:More time to get out of the way?

[ctilsie242]

This happened with Harvey. Right before it made landfall, it took a hard right for Houston, when initially, it was going to go up and pay Austin a visit.

Re:More time to get out of the way?

[Sarten-X]

That's always been the case, though. Those "3 or 4 probable paths" are the most likely out of the thousands of predictions from a dozen different models. Those models, however, have been getting more accurate over the past decade, significantly narrowing the cone of probable locations several days in advance of the storm.

However, slower-moving storms still bring higher risk. Yes, people should have more time to evacuate, but the damage left behind will still be significantly worse, due to the increased flooding and longer duration of high wind, which in turn means more debris impacts. Those who won't (or can't) evacuate face the prospect of surviving not just a day of hiding in a shelter, but days or weeks of canned food, boiling water, and battery power... and years of work to repair the damage.

Re:More time to get out of the way?

[Sarten-X]

One of the interesting trends with winter storms especially is that we just don't care as much. An equal storm does less apparent damage.

A few short decades ago, even a minor snowstorm would knock out power for a few hours. One I woke up and realized my alarm clock wasn't working, I'd have to call and report the outage, and eventually somebody would come around and fix the one service line coming through my area.

Now, the service network can detect its own faults and dispatch repairs automatically. My alarm clock is now my phone, and it runs on its own battery - along with the cell tower. My LED lights and high-efficiency heating don't add nearly so much load to the electrical grid, so when my now-redundant area is automatically switched over to a backup line, that equipment can handle the additional load without any problem.

Of course, building codes have also improved, so a storm of equal power is less likely to damage a newer building. Digital communications don't noticeably degrade as quickly as analog, either. With resilient electrical systems powering streetlights and widespread communications enabling coordination through the storm, the snowplows teams can run better with less risk, so by the time I need to actually travel, the roads are clear. With clear roads, businesses stay open, and life moves on as normal.

It seems to me that most of the big storms that are predicted now are actually big storms... they just don't impact my life so much.

Re:More time to get out of the way?

[CohibaVancouver]

getting people out of the way (who want to get out of the way) is not a problem.

Tell that to people who live on Puerto Rico and other Caribbean Islands.

Re:More time to get out of the way?

[reboot246]

Plus most of the major highways along the coast of the Florida panhandle, Alabama, Mississippi, Louisiana, and Texas run parallel with the coast. Only a few major highways lead away from the coast and even when they make the interstate highways one-way going north, the traffic is horrible.

Re:70 year claim is bullshit

[flink]

They probably have logs of when storms made landfall at various islands as well as ships' logs to give an overall track and timeline and from there extrapolate average velocity. Also ground-based radar goes back further than the 70s, I think, so there should be some fairly accurate data that predates consistent satellite coverage (at least when the storm was over/near land).

In addition, if you are only concerned with the storm around the time it makes landfall, then eyeballs are probably good enough. I'm sure local weather stations kept track of when the eye passed over them and how long it took to pass, which should give you the over-land velocity.