Tornadoes are most common on the central plains of the U.S. in late spring and early summer.
If you can see the tornado
you will see Cumulonimbus clouds before a tornado which are large, dark, anvil-shaped clouds.
It's not that you see the actually air inside a tornado, but you actually see the debris, dust, and other objects that it picks up along the way. Sometimes, however, you see the tornado because of the moist air that's inside of it, which lets you be able to see it, kind of like a visible cloud.
Usually. If you see rotation in the clouds it means a tornado may form. If you see a cone, cyclinder, or "elephant trunk" shaped cloud extending from cloud base a tornado may already be on the ground.
No. If there is a tornado the sky will be over cast an you won't be able to see the moon.
On a weather map, a tornado is often symbolized by a rotating circle or triangle with a tail or hook shape, indicating the high winds and rotation associated with a tornado. Tornado symbols are usually colored in red to highlight the severe weather threat. Additionally, warning boxes or polygons may be used to outline the potential tornado path and affected areas.
Seek shelter. If you can get yourself underground, that's the best place to be. Although many people assume overpasses provide a safe haven this is far from the truth; they are by far the worst place to be as a large tornado will easily suck you out. See related links for video of the infamous 1991 tornado in which a group survived a small tornado under an overpass, and a link to tornado myths.
A tornado can form at any time of day and all tornadoes are dangerous. However tornadoes are most common in the late afternoon and early evening and are most dangerous at night when they are difficult to see.
If you can see the tornado
That would be the United States. It gets more tornadoes than any other country, averaging about 1,200 per year. The United Kingdom is the country in which you are most likely to see a tornado, as it has more tornadoes per square mile than anywhere else in the world.
Those lucky enough to see it as it approached took shelter where they could, but aside from that there was no preparation. There was no warning system in place, so most people did not know it was coming.
Yes. There are hundreds of tornado videos on YouTube.
It is safest to stay underground if you hear/see a tornado.
The easiest and most common place to view sodium chloride is in a salt shaker. It's table salt.
When you see a tornado, go into a secure building or if there are none near you, huddle in a nearby ditch.
That most likely depends on your insurance policy, so it is advisable that you review your insurance polcy to see if tornado damage is covered. If not, insurance for tornadoes can be purchased.
Most national parks have black bears. Do not feed them, however. They are still wild and dangerous animals.