No. Closing the firplace flue will not make any difference in damage to you home. Closing it will only waste time better spent taking cover.
Generally not. If a tornado is closing in on you a car is one of the most dangerous places to be. If you are in a car and a tornado is coming close get out of it and seek shelter in a sturdy building. If no such shelter is available take cover in a ditch or depression.
A tornado can snap a tree in a matter of seconds. See the link below for an up-close video of a small tornado striking a tree.
That varies. If you are close enough to be in the area of the tornado's inflow then the wind will blow almost directly towards the tornado, perhaps a little to the right of that direction. In that case the wind direction will depend on where the tornado is relative to you. If you are beyond the inflow area for the tornado, then nothing about the wind direction would indicate the approaching tornado.
That depends on the tornado. In the very weakest tornadoes it would be possible to stand with some difficult inside the tornado itself. In a strong enough tornado the winds may be strong enough to pull you in from as much as 200 yards away, perhaps more.
There is a good chance that your house will be damaged by high winds and debris.
the flue should be opened
No. You do not need to take shelter during a tornado watch. You take shelter if a tornado warning is issued. If you are in a closet shelter you should close the door; it may not provide adequate protection otherwise.
No. If a tornado warning is issued, you should take cover as quickly as possible. Since tornadoes are usually preceded by rain, there is a good chance you will have closed your windows anyway.
Yes- but open before use.
If the tornado is relatively close and no other shelter is available then yes. Tornadoes are fast moving and unpredictable, you should not attempt to outrun one.
No. The flue must be open to allow the carbon monoxide to escape from the house.
The function that a fireplace fan serves is to distribute heat throughout the room that the fireplace is in. A fireplace fan is ideal because it's probably not safe to sit too close to a fireplace.
in tornado alley which is in Texas and states close to it
The purpose of the fireplace damper is to keep the outside elements, outside. The damper is opened only when there is a fire in the fireplace.
Generally not. If a tornado is closing in on you a car is one of the most dangerous places to be. If you are in a car and a tornado is coming close get out of it and seek shelter in a sturdy building. If no such shelter is available take cover in a ditch or depression.
If a tornado passes near or over a barometer, it will measure a very rapid drop in pressure. How much the pressure drops depends on the strength of the tornado and how close the center of it comes tot he barometer.
The main thing that one should do to make sure that heat is not being lost through the chimney of a fireplace is to always close the damper when the fireplace is not in use. In addition, you can also use a fireplace door or cover to prevent additional heat loss.