Tornadoes...'Tis The Season

Absolutely DO NOT take cover under an overpass

This has not yet been determined to be true. "Experts say" (always a scary phrase) that theoretically, the wind could speed up under the bridge or the suction could increase based on the venturi effect. I spent some time this morning looking for proof - actual measurements.

The only study I could find that actually measured wind, pressure, and more under an overpass was this one:

Tornado-strength winds interacting with a highway overpass featured

Here are some of the findings:

1) The measured dynamic pressures normalized with the freestream dynamic pressures show that when the air flow angles of approach to the overpass were between 50° and 80° just above the overpass, the normalized dynamic pressures were nearly the same as those of the freestream.

Simple terms: the pressures underneath the overpass "were nearly the same as" those outside of the overpass in the free-flowing wind.

2) In all locations and angles of approach, the measured velocities remained the same as, or below the freestream velocity of 190.2 ft/s (58 m/s; 130 mph).

Simple terms: The airflow did not accelerate when going under the overpass

Personally, I'm getting under an overpass, which I did safely the one time I was caught in a tornado. There are tons of "experts" who theorize that's unsafe, but I've yet to see actual proof that it's safer to lie in an open field, as they suggest. You guys do what you think is best. I'm not giving advice, just my perspective.

I would also note that "experts" have told us that red meat, eggs, salt, and sunshine are also bad for you. You can also believe that if you like, but I've made a great life out of doing exactly the opposite of what most "experts" tell you.

Remember, every time science advances, what they're really saying is that up to this point in time, the "experts" were completely wrong. Think about that.

Good point about the experts.

And who was the comedian who said: “My doctor told me to stop eating red meat or I’d have a heart attack. I told him that cows are all red meat and I never heard of a cow having a heart attack “

Good input Brett.

I’m looking at an overpass now and can’t see how it would be much of a Venturi because nothing is forcing or confining the flowing wind under the bridge.

I really have to agree with Brett. I would rather take my chances in an underpass rather than jump into a wet ditch and possible just be sucked up into the tornado or have something fall from the sky on top of me.

So, my question is this: let’s say you want to get under an overpass but there are already vehicles under it.

Would you get out of your truck and try to get as high under the deck as possible? And if you stayed in your truck, even under a bridge, would you get in the bunk and secure the safety net?

And if you were in a daycab, there would be different problems to consider.

The movie “Twister” had a tanker truck flying through the air at on coming traffic. Probably Hollywood BS, but the wind strength of a tornado could certainly flip a tractor-trailer over. Maybe even roll it if a near hit.

Good question BK.

May pose this question to a company safety department to see what “expert” answer comes back.

Just close those front curtains, jump in the bunk, pull the pillow and blankets over your head, and say "Not Today Satan!"

Depending how near the tornado is I'd park outside the bridge and run under. When I talk about getting under I'm talking about the crevices up top where you occasionally find homeless finding shelter. If it's really close that there's alot of debris being thrown I think staying buckled and covering your head would be the best chance you have. The idea of getting out and into the open I never understood.

And if you were in a daycab, there would be different problems to consider.

like grabbing my purse while I flee?

The movie “Twister” had a tanker truck flying through the air at on coming traffic.

That movie was originally planned to be filmed in California and the UK but they ended up filming all of it in Oklahoma with the exception of the exterior shots on Aunt Megs house which is 30 miles west of me in the small, 2500 people, town of Eldora. It was before my time in this area but people are still talking about it.

A tornado hit our family farm near Nashua, Iowa when I was a small kid in early 60’s.

It got dark at 4pm. We got into the cellar in a corner space that my parents kept setup for storms.

The storm took out several large trees and a barn door.

My Dad drove us around the neighborhood farms afterwards to look at damage.

I saw things like straw sticking in wood and cows impaled by boards. Heavy tractors rolled over. Buildings demolished.

Years later the town of Charles City, IA (where I was born) was essentially wiped out by a large tornado.

My wife was at the Downstream Casino near Joplin, MO when Joplin was hit and wiped out in 2011.

Dang...alot of good topics lately.

I feel like I've been commenting too much this afternoon but I have to comment on this one because it literally happened to me lol...in Maryland of all places and the only time I've ever been there.

This was years ago when I was still brand new with Swift and still pulling reefer (only pulled reefer my first four months in trucking). All I remember was I had just delivered a load in MD and the closest approved trailer washout was this guy's house basically, about a mile or so from a major truckstop. I got there and you basically had to pull through the guys property in a circle around his house and back up next to the road on the other side (his house was on a corner lot). Super weird but I digress. The guy wasn't there and said he'd be there within the hour. While I was sitting there waiting I started getting all these tornado warnings on my phone but I didn't see anything when I got out and looked around so I kept waiting. It wasn't even windy and my dumb*ss thought I was fine. I kid you not, literally all of a sudden all the trees across the way started shaking like crazy and it started getting super windy and all these really low wispy clouds came out of nowhere and it got dark FAST. I tore tf out of there and made it down to the truckstop down the road and ran inside as fast as I could. By the time I hit the road on my way to the truckstop it was already pouring and I was praying that the wind wouldn't flip my truck.

I never did see the funnel but the people at the truckstop said right before I got there the lights in the parking lot were swaying all over the place and that a tornado had gone right by us. I don't remember if they said it actually touched down or not but I will never forget that experience. I did have another time I actually saw a tornado in Colorado east of Denver along I70 somewhere in the vicinity of Limon iirc but I wasn't close enough that the wind affected me much. I saw the same low wispy clouds and dark sky I saw before but the tornado was several miles away and it wasn't raining so I just kept driving like everyone else and got out of there as fast as possible.