Unintentional comedy at its finest
I'll preface by stating that I'm a huge Bruce Campbell fan - that said, Tornado! pushes the cheese factor past the usual Campbell fare. This one definitely falls into the category of so bad it's good, especially if you find yourself trying hard not to laugh through the most serious parts of the film.
Here's a few of my favorite slices of this pie:
1) Apparently humans are unable to detect tornadoes without an official warning from NWS or at least a siren blaring. The good folks in the soon to be tragically destroyed town continue to stroll down the street through hurricane force winds, flying debris, and ominous howling, all the while remaining blissfully unaware until the sirens start.
2) Stealthnados - a creation of global warming, stealthnados pop out on clear and sunny days, only announcing their presence once they're upon the prey. Once the victim is aware of the stealthnado, the skies suddenly darken, and despite being able to top 100 mph in a vehicle, it is better to abandon your vehicle and lie in a ditch that's less than a foot deep. Anyone else seen the video of tornadoes scouring pavement off of roads?
3) Tornadoes are either really blurry, or they suffer from nearsightedness. This might explain how they're able to sneak up on people so easily, and why they miss so many folks once they pounce. It's hard to catch your prey with really poor vision.