When tornadoes are approaching they look like huge funnels. Tornadoes can approach an area very quickly You are advised to leave an hour before you can see the storm.
Go to a safe place and stay in the basement
Tornadoes can destroy the trees that birds use for nesting, and can potentially kill birds that get swept into the vortex. This has actually cause some concern an a few occasions when tornadoes have threatened the nesting sites of endangered birds.
Tornadoes cannot be prevented. Current technology can warn us of an approaching tornado, but can't do anything to stop it.
people call in and tell them or a radar picks up the approaching tornado
Go slow when approaching
Winter was approaching and caused birds to immigrate south.
You can say "fast approaching" sometimes. For example: Winter is fast approaching. There is a fast approaching car on the racetrack. It was fast approaching the time to go home.
A better warning system will allow people to better prepare for an approaching tornado, meaning that fewer people will be killed or injured in tornadoes.
Animals use a communication signal to warn others that a predator is approaching. Birds use songs to warn others of predators.
Yes, tornadoes have been known to kill birds and not always leave them in one piece. While a hammer could easily become a projectile during a tornado, its chances of hitting a bird are probably quite remote.
They can. The belief that hills stop tornadoes is a complete myth.