Saturday, September 9, 2017

Hurricane Irma: last-minute alarms and excursions


As Hurricane Irma approaches Florida, there are a number of last-minute (or, at any rate, last-day) events that are causing consternation and monkeyhouse among my friends and correspondents there.

Hurricane Irma's predicted path was (a few days ago) along the edge of the Atlantic Ocean, next to Florida's east coast.  As a result, a large number of people evacuated their Atlantic shore homes;  but many found that the roads northwards were blocked, so they turned west instead, heading to Florida's west coast on the Gulf of Mexico.  Guess what?  Irma's predicted path has shifted westward day by day, until its eye is currently forecast to track along Florida's west coast.  That means hundreds of thousands of evacuees have fled right into its path.  With the roads as blocked as they are by last-minute evacuees, they may not be able to get to a safer area in time.  This could turn nasty.

The same applies to those who evacuated north - but not far enough north.  Irma is currently predicted to track to the west of Atlanta, ending up as a tropical depression over west-central Tennessee, where it'll bring a couple of days of strong winds and heavy rain.  (My former home in Nashville may be in for a wet few days.)  That's good news for Savannah, GA, which evacuated in expectation of storm surges and heavy rain . . . but a lot of its people fled west, right into Irma's currently predicted path.  I suspect they're not going to enjoy themselves.

Also, Aesop over at Raconteur Report did some fact-checking.

I pulled up a random 7.5 minute topo of Florida's west (Gulf-side) coast, in this case, the Ft. Meyers SW grid.

Unlike some topos, where the elevation stadia are 40-ft increments, FL's on the USGS map for this region are measured in 5-ft increments.

I knew FL was low-lying, but I didn't know just how low-lying.

We're talking Netherlands-low low-lying. Nawlins 9th Ward low-lying. Damn near Death Valley low-lying.

There is no spot on the entire map topo above 10' over sea level.

. . .

The predicted storm surge for the danger area is currently at least 10'. The total range predicted is 5-20'.

Everything on this map in gray or red is land less than 10' in elevation:



IOW, where most of the people live.

If Irma hugs the western side as forecast, pretty much the entire southern half of the west coast of FL is toast, from Saturday night into Monday afternoon.

And that's just storm surge, before a foot+ (6-20+ inches per NOAA forecast) of continuous rainfall for a day and a half is factored in.

Harvey?  Just a warm up.

Looks like Irma will be biblical.

There's more at the link.

Irma may end up being worse than Katrina, in terms of the number of people affected and the length of the coastline involved.  Good luck to all involved.  We'll be praying for you.

Peter

15 comments:

Akatsukami said...

The first three paragraphs make me wonder if strengthening, if not the whole house at least a safe room, and hunkering down wouldn't be better than trying to evacuate in the face of an uncertain storm track and a skillion other people.

Old NFO said...

Yep, they're in for it, unless it continues tracking West.

Anonymous said...

Gonna be bad regardless of how you prepare.

Peter, you left out the good quote from 'Reconteur':

"FL isn't going to need the Cajun Navy.
They're going to need the entire Redneck Fleet.
This is going to make Dunkirk look like a pool party."

I'm in North Alabama and we have family from South Florida up here; Irma is going to impact all the Southeast for quite a while. Going to be a wild fall, socially & economically.

Everyone take care & stay safe.

JD

paladin3001 said...

Considering most of Florida is swamp or near swampland this elevation thing isn't that much of a surprise. Just hope nothing majorly bad happens to those that are stuck and can't get out. Been reading about people that have friends that are unable to leave for a variety of reasons.

Andrew said...

Akatsukami,

Yes, strengthening the house is a real 'thing' in hurricane country. A homeowner can retrofit hurricane straps from the roof trusses to the walls. Replacing asphalt shingle roofs with properly installed metal roofs will make the house much better. Retro-fitting storm rated windows, doors and especially garage doors, will increase the safety of the whole house, which is better than just making a safe room.

The FedGov actually has recommendations for hardening a small room for high-wind environments, and is very applicable in 'hurricane' areas as tornadoes are often spawned by 'canes.

Best solution is to do both, build to or exceed current standards or retrofit the whole building as much as possible, and have a safe room built or retrofitted.

The only reason to evacuate is if one is in a known flood or storm surge area. You have to be careful, though. My mother lives on the eastern barrier island south of Cape Canaveral, and her home is actually higher above the water table than her grandson who lives in West Melbourne, due to the swamps and such. His girlfriend evacuated to Mom's house (actually safer, really, house constructed above Hurricane Andrew standards.)

Problem with 'bugging in' is mandatory evacuation rules. Some locals threaten to arrest and imprison non-evacuees.

And then there is where most shelters are set up. Schools, which are notoriously built to lesser standards than commercial or residential buildings, are deathtraps in high-wind environments, whether in hurricane, tornado or earthquake regions. It is a situation where ou can die in a small group or evacuate and die in a large group.

Not to mention what we are currently seeing. Trying to evacuate from one of these storms is like an ant trying to run away from some kid's shoe. The ant has no ability to correctly analyze the shoe's position in the future.

Anonymous said...

Peter and all, thank you for best wishes to us Floridians. Please note mandatory evacuation DOES NOT mean you would be dragged to jail or harassed by the law enforcement in any way :) :) It simply means you are on your own and no emergency services will be provided. Many of us, especially in concrete buildings, decided to stay, which is also advised if you cannot evacuate safely, as some of my elderly neighbors. Most hospitals are not evacuating either. So far, the government, utility companies and everyone else have been doing a great job. Much better than in the past. One more thing - in terms of up to the minute information, response to questions and support from friends around the world, Twitter has been my life-line. So even if you hate social media I would recommend to anyone in a potential natural disaster areas to get an account. --Anna in So.FL

Anonymous said...

"Most"?

Most people are stupid. This is proved by the millions willing to live in environments that are subject to predictable events, and are unwillingly or unable to invest preparedness principles required to somewhat survive such an event. Solution: move.

"Not everyone can afford to move out of (fill in the blank)."

Oh, but you can afford the forced relocation, damage, injury or death from predictable events?

"But but but, I want to live where I only need to wear shorts and flip flops my whole life...."

Fine...just don't make me pay for it.

No more bailouts for stupid.


B said...

What Anon said.

If we'd charge these folks what they SHOULD be charged for flood insurance, then they'd never build there, nor would the banks give loans.

I am all for flood insurance. But not SUBSIDIZED flood insurance. Especially not hen it is the Taxpayer that does the subsidizing.


Having said that, I am praying for those who are affected.

Andrew said...

Well, let's not fund tornado insurance, flood insurance, earthquake insurance, and basically not give gov money to any victim anywhere.

Rail disaster, nope, you moved near a rail line. Air disaster killing people on the ground - nope, you moved under an air corridor. Skyscraper gets gouged by a hijacked airliner - no money for you. Asteroid falls and kills a bunch of people, tough nuggies.

How about, instead, allow gov money if the people rebuild to the new standards, including storm shelters for tornadoes and such.

A lot of people live near ports and manufacturing facilities that are usually built around ports.

Coastal areas have, since man first started walking, been the base of civilization. It is easier and cheaper to build along flat, coastal plains than go the Heidi route and build in the mountains, where you have to worry about snow, avalanches, rock slides, glaciers, firestorms, and a whole other group of natural disasters that make living in the mountains a real pain in the arse (see the movie "7 Brides for 7 Brothers" for a good example.)

What we should be doing is building storm shelters, better drainage, better levee systems. Quit allowing democratic politicians take storm abatement monies to line their own pockets, as we saw in New Orleans and now Houston.

Heck, I thought the way to rebuild New Orleans was to dredge the river channels and pour the spoils into the flooding areas, using the levee walls as the lowest level of the dirt fill.

0007 said...

I live on FL's west coast, about halfway up. The house I am sitting in as I type this was built in 1923 and is >50 feet above sea level. I was born here 70+ years ago and grew up across the street from where I now live. And I told my friends back when this storm was coming toward us that it would track through the FL straits and out into the Gulf. (Good friend brought his family up from the keys and KNOWS already that his house won't be there when this thing passes by there.)
I 'spect we are going to see some heavy rain and seriously gusting winds here, but I have a case of mex cola and a big bottle of Captain Morgan 100*, so I figger to sit back and see what we see.
Wouldn't be the first time the inside of this place got wet. 'Course that was because it started to rain AFTER I had pulled off the old shingles and before I got the new ones down...
Annnd my house guest just discovered that she won't be able to go down the street to the local 7-11 and get cigarettes. Oh, the humanity...

Adam said...

Peter,

You might like this site - current wind patterns around the world.

https://earth.nullschool.net/#current/wind/isobaric/1000hPa/orthographic=-76.99,22.00,3000/loc=-81.578,24.144

Alphonse said...

After hurricane Sandy hit NJ (they're still referring to it as "superstorm" Sandy because using the word "hurricane" would have invoked the much higher windstorm deductibles on insurance policies) building codes changed. In certain areas enw construction must be above predicted storm surge levels, eg., on stilts.

The air space between the first floor and ground may not be used as living space, but is available for vehicle parking and storage if "breakaway" walls are installed to allow storm surge to easily destroy the walls and flow through.

I wonder if Florida is smart enough to implement similar building code changes after Irma; the 1995 code changes incorporated lessons learned from hurricane Andrew.

The Neophyte said...

Laughed at your map a little. Most of that red area in the southern part of the state is the home of alligators and pythons. I don't think they care about evacuating. Having said that, I live in Pinellas county, the spit of land that is west of Tampa Bay. We haven't had a true hurricane strike here since 1921. The amount of build up on the beach communities (read barrier islands) in the last century is astounding and if this thing does actually track the coast, especially until it gets here, it could be truly catastrophic. One good thing is much of the construction has occurred since Andrew and so is at much safer standards than before 1992. But there is plenty of pre 1990 homes too and I fear what might happen to them. I'm hunkering down and hoping for the best - off the beach.

0007 said...

Yeah, Alphonse, all the new construction in Pinellas inside the "100 year flood zone" has to have the ground floor as storage only space, not "living space".
'Course that makes for some really ugly new-built three-story houses on some of the old dredged-land fill developments.
Got a friend out on the original Treasure Island dredge-and-fill still in his house built in the early '60's on land that the wife and I used to "park"(IYKWIM) on but all up and down the fingers the old single story houses are being torn down and replaced with 3-story McMansions.
Think about that, buy a house for $500-750K, tear it down and build a million dollar house on the lot.
say howdy to the Neophyte there.

sysadmn said...

I've been following the coverage and analysis of Irma at Conservative Treehouse (https://theconservativetreehouse.com/category/hurricane-irma/), as they live in the area and evacuated early. They also link to the National Hurricane Center advisories.

In particular, this article (https://theconservativetreehouse.com/2017/09/08/understanding-the-unique-challenge-to-south-florida-during-irma/) discusses why it's difficult to evacuate south Florida.

This was prescient:

For our friends in the Westward Keys and Southern Gulf Side (South West Florida), please pay particular attention to this current storms path. Unlike the Eastern coast of Florida the South West coast (Gulf Side) is primarily made up of recently populated “shallow water” Gulf barrier Islands. A Category 5 storm that skirts the Western coast of Florida, from Ten Thousand Islands Northward to Sarasota, and maintains inflow energy from the Gulf of Mexico, is a topography changing event..