Semi tanker drives through flooded road - GIF

[cmarlow]

Greenie. I grew up around fast water. I know what it looks like. I know what it does.

Take a real good look at your Aussie video. The water is not flowing anywhere near as fast. Look at how little it is piling up against the obstructions in the current. If it was flowing as fast it would be piling up against the barriers much more, like it is doing in the first video, and your buddy's little pickup truck would have been gone downstream. The main wave in your Assie video is straight forward from the pickup pushing the water ahead of itself. If the side current was as strong the water would have piled up against the door and been coming in the window

The driver in the first video was an idiot for driving into that stream, and an even bigger idiot for driving too fast for his tires to keep contact with the surface instead of hydro-planing, and an incredibly huge idiot for not stopping as soon as he felt his truck drifting.
Typical hero mentality. Hopefully the driver in the first video (like I already said) was smart enough to just sit on his truck instead of thinking he could hop down and walk back to dry land because he would not have made it. However you never know with these "supermen" who think the laws of nature do not apply to them.

I have driven (large) trucks through water where my knees got wet on mine roads during spring floods. I have a natural aversion to doing so. Not only is the water cold but you have no way of knowing what is under your wheels, you might be driving into potholes, a rock garden or a clay grease pit.The water also tends to screw up any electronics under you, as well as contaminating most of your lubrication. Pumping large quantities of grease through every zerk fitting on your undercarriage until the grease comes out as grease instead of white cream, draining and changing all diff, tranny, and hydraulic oils does not make for a fun Sunday.

[Fluffle-Valve]

He lost it at the start as soon as he hit the water. You can see that he drifted off to the right from the start.

[markonevet]

Semi tanker drives through flooded road.

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Previously:

Car catches fire after driving through flood - GIF
Arizona flash flood - GIF
Flash flood swallows construction site - GIF
Flash flood smashes restaurant facade - GIF
Flash flood barriers - GIF

Fact: Water is 832 times denser than air, so a 10 mph flowing river/stream that has a submerged object is pushing with a force equal to a wind blowing at 8,320 mph. When you see an equation like that it should not be surprising when big objects get moved so easily with swift-flowing water. It is deceiving and no wonder so many ignorant people get caught and drown.

[cmarlow]

Yup, and you mention submerged objects, so lets consider buoyancy. If the object is in the water it is trying to float, even if it is denser than the water. even if it is only partly submerged.. Its weight is reduced by the volume of the water it displaces, which means it has even less downforce to produce friction and resist being pushed. If the object can float there is no resistance at all unless it is tied to an anchor.
If you try wading through moving water and it is only ankle deep the water is trying to float your feet and you will have about 7 or 8 % less downforce because of it. If you are in the water waist deep you have lost almost half of your downforce as well as greatly increasing the area the water is pushing against. Waders have been drowned in fairly shallow water because when they got knocked over a foot got trapped between rocks or similar, holding them in the current as it washed over them and making it impossible for them to get up.

[cmarlow]

Yup, and you mention submerged objects, so lets consider buoyancy. If the object is in the water it is trying to float, even if it is denser than the water. even if it is only partly submerged.. Its weight is reduced by the volume of the water it displaces, which means it has even less downforce to produce friction and resist being pushed. If the object can float there is no resistance at all unless it is tied to an anchor.
If you try wading through moving water and it is only ankle deep the water is trying to float your feet and you will have about 7 or 8 % less downforce because of it. If you are in the water waist deep you have lost almost half of your downforce as well as greatly increasing the area the water is pushing against. Waders have been drowned in fairly shallow water because when they got knocked over a foot got trapped between rocks or similar, holding them in the current as it washed over them and making it impossible for them to get up.

There are a few spots with nice little white water chutes on our river. Canoes that get trapped sideways against boulders never come out the same as when they went in.

[mklotz]

Fact: Water is 832 times denser than air, so a 10 mph flowing river/stream that has a submerged object is pushing with a force equal to a wind blowing at 8,320 mph. When you see an equation like that it should not be surprising when big objects get moved so easily with swift-flowing water. It is deceiving and no wonder so many ignorant people get caught and drown.

Your "equation" is simplistic but I think there is a problem. If you're going to equate the kinetic energies of air and water, I think the equation should look like

ma * va² = mw * vw²

where:

ma = mass of air
va = speed of air
mw = mass of water
vw = speed of water = 10 mph


For equivalent volumes of air and water we can substitute the appropriate densities for the masses, which leads to:

mw = 832 * ma

and the equation becomes:

va = vw * sqrt (832) = 10 * 28.8 = 288 mph

The original equation is too simplistic and ignores some important effects but, taking it as presented, the 8320 mph wind seems unrealistic.

The 832 is a bit off too.

Water density is 1000 kg/m³
Air density is 1.225 kg/m³

1000 / 1.225 = 816.33

[cmarlow]

288 mph is still a lot of wind.

[Hoosiersmoker]

All I can say is: DAM!

[mklotz]

288 mph is still a lot of wind.

Yes, it is but at least it's feasible, if unrecorded, on this planet. For 8000+ mph wind you would have to go to Jupiter or some such. Note that there are recorded instances of semis having been tipped over by wind in the southwest deserts.

The whole idea of equating the kinetic energy is suspect because the wind and water impinge on different areas of the truck. I haven't given it a great deal of thought but it would probably be more realistic to compare the drag forces exerted on the truck by wind and water. Using the drag equation would force you to deal with the drag coefficients for those two fluids and the vastly different areas associated with the forces they generate.

[cmarlow]

The Fujita scale of tornado intensity:
https://www.weather.gov/ffc/fujita

I did not mean unfeasible. I just meant it is still a lot of wind. 280 mph wind speed is fast enough to rank as level 5 (incredible) on the Fujita scale.

Lucky we seldom see much deep water moving at 10 mph over roads, through towns or into nuclear reactors. When we do we call it tsunami like the ones that hit asia a few years ago.

OK, lets not think Tsunami. Lets just think of a regular flash flood in a canyon happily picking up car size boulders and rolling them along.