Mobile homes and wind

[Dargo]

As many of you may recall, there was a terrible tornado that swept through a mobile home park as well as 20 miles of frame built homes in November of 2005. All 28 of the deaths occurred in the mobile home park. There has been study after study and group after group going through the destroyed park. This morning there is a long article in our paper saying that:

"Members of the Department of Civil Engineering and Wind Science and Engineering Research center at Texas Tech University examined the damage at Eastbrook shortly after the tornado.

Their observations led them to determine faulty anchoring of some mobile homes was a major component of the destruction.

This finding was addressed in a report for the National Institute of Standards and Technology. According to Larry Tanner, one of the Texas Tech civil engineers who did the report on Eastbrook, the deeper problem lies in the lack of federal regulation.

Through his investigations at Eastbrook, Tanner found that by making a few changes, mobile homes could safely ride out a 50-60 mph windstorm."

Now what bothers me is the last sentence, the part about being able to safely ride out 50 to 60 mph winds. Yesterday at my house we had a gust of 67 mph during one of the brief storms. Is he saying that even properly tied down that a mobile home can not survive such a wind? If so, doesn't it seem extremely dangerous to live in one of them in an area that may have severe thunderstorms, tornadoes, or hurricanes? Is it just me, or doesn't their goal of being able to with stand 50-60 mph winds seem extremely low?

 

[Melensdad]

doesn't their goal of being able to with stand 50-60 mph winds seem extremely low?

YES! I can't even imagine such low wind loads as meeting building codes here in the midwest. The midwest is not called Tornado Alley for no reason.

Hurricanes and Tornadoes are very different, but the results are often the same. A tornado is much more localized but the windloads are easily over 100mph. A hurricane can span an entire state. Either way, the winds are extreme.

 

[DaveNay]

Is it just me, or doesn't their goal of being able to with stand 50-60 mph winds seem extremely low?

If that is the implied standard requirement for mobile homes, I'll be in my truck, thank you.

Bob, even 100 MPH is low for a tornado. We had a 106 MPH gust last spring, and that was just a "normal storm" (I quote that because it was obviously not normal, but it was not declared a tornado by the NWS). Tornados have been recorded well into the high 200's, but as far as I know they always destroy the measuring equipment, so they don't know the maximum winds from direct measurment. I think doppler radar measurements have confirmed the winds at least that hig, or higher.

 

[Melensdad]

All I know is that I have 3' and 4' wide eves on my house and the west wall of the house faces a wide open field and sits on top of a ridge. Prevailing winds come from the west and the builder and the architect both were concerned that the 3 story tall west wall with wide roof overhangs, sitting exposed to the westerly wind would cause roof problems so I have 'hurricane straps' that hold my roof onto the walls of the house when we get hit by big storms. Even with that, when the big storms with very high winds hit, our house shakes.

 

[DaveNay]

All I know is that I have 3' and 4' wide eves on my house and the west wall of the house faces a wide open field and sits on top of a ridge. Prevailing winds come from the west and the builder and the architect both were concerned that the 3 story tall west wall with wide roof overhangs, sitting exposed to the westerly wind would cause roof problems so I have 'hurricane straps' that hold my roof onto the walls of the house when we get hit by big storms. Even with that, when the big storms with very high winds hit, our house shakes.

Very sound reasoning on the part of you and your builders.

 

[Dargo]

I realize that no mobile home would have been able to take the F4 tornado we had, but I certainly wouldn't want to live in a home that they brag about being able to withstand a 50 to 60 mph wind! As you can see from the Fujita Scale, an F4 will take out most everything. However, it is commonly thought that the suburban theory that tornados always hit mobile home parks is because all it takes is an F0 or an F1 to destroy them. The same "tornado" that will take out a mobile home park will only result in some broken limbs and maybe a fence down in well built areas. The thought is that most all of those "tornados" are not ever reported and we only hear about the ones flipping trailers over. If it only takes a 50 or 60 mph wind to do so, no wonder we always hear about trailers being hit by so called tornados.

 

[Glink]

We had a sustained straight line wind a year or so back of about 80 mph, a durachio I think is the term, that toppled trailers and leveled barns from Corydon to nearly Scottsburg in in Southern IN. Wind came from the north, tremdous timber damage, trees ripped over with roots exposed. Pretty strange. Also grew up in Madison in '74 when the F4 came through the center of town........... truly awesome.

 

[OhioTC18]

Mobile homes are made for different regions of the country. And as such may be constructed differently. Almost all of them (since the 60's) have straps that go up under the siding and across the top to the other side. If anchored properly they will withstand a real hefty wind. A lot more than 50 MPH. Mine was never anchored. It did rock during a violent storm, but an F4 will rip it to shreds and leave the strap blowing in the wind.

 

[Dargo]

but an F4 will rip it to shreds and leave the strap blowing in the wind.

The F4 we had picked up a Harley Heritage (dunno what model that might be) and dropped it 3 miles away in a guy's attic. The F4 also took out all trailers in it's path and only left the pad. Some were strapped down but it literally ripped the straps from the pad along with a chunk of the concrete. I think the goal should be for someone in a trailer to have a chance to live through an F1.

The F4 took down the concrete grandstands of Ellis Park horse track, wiped out their stables and sent their 2000 pound sign over a mile away into some trees. Over a year later, it is still very easy to follow the path of the F4 from the air.