ALL SHELTERS UNSAFE? MAX WINDS?

[john186292]

With global warming slated to increase the ferocity of storms, please estimate the new maximum wind to plan against.

(and, what has been the max so far? about 210?)

TORNADOES
Since canes oft spin off tornadoes, is it not true that current shelters are really not safe? They don't look like they could handle a tornado.

"ROOF JUST BLEW OFF!"
Years back, i heard on the radio that a shelter full of people in Mississippi "just had its roof blow off." Oddly, i heard nothing more then or later, about that sensational bit of news. Anyone know about this story? About six to eight years back.

GRIDLOCK = DOOM
With gridlock arguing for planners to make more use of in-town shelters, we ordinary citizens need to learn about shelters....to tell when they are making huge errors in shelter design (or feeding us balony). Huge errors,like the planners who have allowed the gridlock problem to develop.

Shelter errors, like not able to wall out storm surge flooding, or keep it away from generators and the gasoline...twenty feet for two weeks is the expectation for here.

KEEP SMILING - THE SUN ALSO RISES,
John New Orleans

[wxman57]

Last week, the man in charge of Haag Engineering, one of the foremost wind damage engineers in the world, spoke at our local AMS meeting. One of his big gripes was the Fujita scale, which categorizes tornadoes based upon damage to structures. He showed picture after picture of identical homes, side-by-side. One home would be completely destroyed - roof gone, walls blown out, while the home next door had not a shingle missing and virtually no damage. So one house received F2-F3 damage and the house next door received maybe weak F0 damage. He estimated that the winds were under 75 mph, as that's about the level where shingles are dislodged from a roof (among other factors). But this tornado was rated an F2, indicating much higher winds.

The problem was that on home 1 (F2-F3 damage), the garage door was not properly secured and the front door blew open. Once a structure is compromised, it's easy for even F0 winds to completely destroy a structure. Home 2 had a reinforced garage door and a more secure front door. Wind could not get inside Home 2 and it survived with hardly a scratch. So what was this tornado? F0 or F2-F3? His argument was that the Fujita scale doesn't take into account poor construction techniques, and that the tornado in question was only a weak F0.

The moral of this story is that if you want your home to survive a hurricane, even a weak one with barely 75 mph winds, the most important thing to do is to make sure your roof is tied down to your walls, and your walls are securely fastened to your foundation. The garage door is typically the weakest link in any structure. If the wind blows in a garage door (and it doesn't take much wind to do that), then your home may be blown apart in short order. There are aftermarket kits that allow you to bolt the bottom of your garage door to the cement floor before a storm. Such reinforcement can save your home. All windows must have 3/4" plywood on them, as 1/2" plywood flexes too much and could lead to window breakage and then total destruction of your home.

Oh, and if you want to read a good article about global warming (or the lack thereof), I suggest the following:

http://www.intellicast.com/DrDewpoint/Library/1305/

[shaner]

Wxman, as a newbie and complete amatuer, I certainly did not want to step on any professional met toes here. But, I immediately thought of the article you linked to as soon as I read John's first line. Global warming is a hoax.

As far as wind damage goes, we have average construction techniques today which can withstand horrendous winds. The houses are slightly more expensive to build this way, naturally. The problem is, human greed and the desire to cut corners. Andrew showed us that with the way he destroyed shoddy construction in Homestead.

[MScoast]

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"ROOF JUST BLEW OFF!"
Years back, i heard on the radio that a shelter full of people in Mississippi "just had its roof blow off." Oddly, i heard nothing more then or later, about that sensational bit of news. Anyone know about this story? About six to eight years back.

This was during Hurricane Georges in '98. I believe it was a school gym in Pascagoula. The roof came off of the gym and they had to transport all of the people to another shelter.

[weatherluvr]

Wxman, that's a very interesting take on damage rating on structures. I've heard lots of stories about one house being leveled, while the next house looks untouched. This type of damage was often attributed to suction vortices, causing very localized damage swaths. This puts such damage patterns in a whole new light.

Similar damage patterns were also observed after Andrew, with almost a checkerboard pattern of destruction.

BTW, John, hurricane-induced tornadoes are usually on the weaker side, F0 to maybe F2 at best, so they're not that much stronger than the max winds of the hurricane itself. They stand out more because they usually occur away from the center, normally the right front quadrant.

[stormchazer]

This is a pet issue for me. Below are Dr Grays discussion on Global Warming from the American Meteorological Society conference in Denver and can be found on their website:

Dr. Gray hypothesizes that it is not possible for a doubling of anthropogenic greenhouse gases to cause a 2-5 degree C global warming as indicated by most GCM modeling studies. He feels these numerical models appear to be compromised by three basic flaws: 1) the assumption that an increased hydrologic cycle leads to increased upper-level water vapor - the opposite is more likely, 2) the inability to predict global ocean circulation on a long-time scale, and 3) various numeric and viscosity problems. He believes we should not rely on these global simulations as justification for fossil fuel reductions at this time.

He further postulates that observed global temperature increases during the last 25 or 100 years (where they have been reliably measured) are probably of natural origin. Various natural processes that can lead to such global temperatures were discussed, such as reduced mixing in the oceans and salinity differences.

A lively discussion followed with many questions from the audience. This is just what Dr. Gray would like to see happening in a larger scale - more discussions on the topic with dissenters and proponents.

Attendance: 75---Andrea Adams.

I am not anti-enviroment by any stretch but their is those with an agenda that do not let facts get in the way of their assertions. Since we as people tend to be of the like where if "we here it enough it must be true" then we believe it. We are in a period of increased hurricane activity just as we were in the mid-20th century. Climate works in cycles.

[Mr Bob]

With global warming slated to increase the ferocity of storms, please estimate the new maximum wind to plan against.


KEEP SMILING - THE SUN ALSO RISES,
John New Orleans

This is a very flawed theory...If you were to assume that human interaction is causing climate change (which I do NOT), there are still a myriad of possibilities of effects that no one has a handle on. Given that an F4 tornado can strike most anyplace east of the Rockies, you should probably prepare for 250mph winds if you really think the odds favor you getting hit by one...That ought to relieve you of any hurricane worries.

[AussieMark]

BTW, John, hurricane-induced tornadoes are usually on the weaker side, F0 to maybe F2 at best, so they're not that much stronger than the max winds of the hurricane itself. They stand out more because they usually occur away from the center, normally the right front quadrant.

Hurricane Hilda(1964) and Carla(1961) produced a F4 tornado so there are exeptions to the rule that only weak tornadoes accompany hurricanes.

[weatherluvr]

BTW, John, hurricane-induced tornadoes are usually on the weaker side, F0 to maybe F2 at best, so they're not that much stronger than the max winds of the hurricane itself. They stand out more because they usually occur away from the center, normally the right front quadrant.

Hurricane Hilda(1964) and Carla(1961) produced a F4 tornado so there are exeptions to the rule that only weak tornadoes accompany hurricanes.

Sure there are exceptions to that. I believe Gilbert spawned an F3 tornado in Texas that caused some fatalities. But generally you don't see the intense updrafts, instability, or dry air aloft that are necessary ingredients for Plains-style maxi-tornadoes.

[Stormsfury]

Wxman, that's a very interesting take on damage rating on structures. I've heard lots of stories about one house being leveled, while the next house looks untouched. This type of damage was often attributed to suction vortices, causing very localized damage swaths. This puts such damage patterns in a whole new light.

I thought the exact same thing in relation to the multiple-vortex tornado. The suction vorticities are believed to add 100 mph of wind (generally in the stronger tornadoes) within the large scale tornadic circulations. Generally with such tornadoes, the proof is in the marking on the ground (seen from the air) with a spiraling pattern of intense damage along the same path as the tornado.

BTW, John, hurricane-induced tornadoes are usually on the weaker side, F0 to maybe F2 at best, so they're not that much stronger than the max winds of the hurricane itself. They stand out more because they usually occur away from the center, normally the right front quadrant.

Generally the tornadoes, like weatherluvr posted occur 100 to 200 miles away from the center in the northeastern quadrant. Once in a while, an exception to the rule occurs with a stronger tornado developing from a hurricane induced tornado, but generally, they are weak and very short-lived.

SF

[ColdFront77]

I would assume it is also not impossible to have [short lived] tornadoes in other quadrants of a hurricane; but yes the northeastern quadrant has the greater chance in the northern hemisphere.