What are tornadoes?

A tornado is a destructive force of nature. It is a violently rotating column of air extending from a thunderstorm to the ground. They are capable of creating tremendous destruction with wind speeds up to 250 mph or more.

How are they formed?

Thunderstorms in warm, moist air in advance of eastward-moving cold fronts can often cause tornadoes. These thunderstorms develop along a "dryline," which separates very warm, moist air to the east from hot, dry air to the west. These torando-producing thunderstorms may also form as the dryline moves east during the afternoon hours. Tornadoes can also occasionally accompany tropical storms and hurricanes that move over land.                                                                                      More specifically, this is how they form:                                                                                                            Before thunderstorms develop, a change in wind direction and an increase in wind speed with increasing height creates an invisible, horizontal spinning effects in the lower atmosphere. Rising air within the thunderstorm updraft tilts the rotating air from horizontal to vertical. An area of rotation, 2-6 miles wide, now extends through much of the storm. Most strong and violent torandoes form within this area of strong rotation. 

Where are tornadoes common in?

They are most commonly found along the front range of the Rocky Mountains, the Plains, and the WesternStates. however, they can form almost anywhere.

How violent can tornadoes get and how weak can they be?

Weak tornadoes, 69% of all tornadoes, last about 1-10+ minutes. They cause less than 5% of tornado deaths, and their wind speed is less than 110 mph.                                                                Strong tornadoes, 29% of all tornadoes, last 20+ minutes. They cause almost 30% of all tornado deaths, and their wind speed is 110-205 mph.                                                                                              Violent Tornadoes, 2% of all tornadoes, last an hour or more. They cause 70% of all tornado deaths, and their wind speed can be anything above 205 mph.

How can you tell when there will be a tornado?

You can listen to the radio and watch the news for any warnings. Also, look for dark, often greenish skies, a wall cloud, large hail, and a loud roar similar to a freight train.

Remember, tornadoes can occur almost anywhere so always have a family plan.

If you want to see some tornadoes on video, click this link: http://www.youtube.com/watch?v=43VoMesUd2Q

Some pictures:

~Jess

Source: http://www.nssl.noaa.gov/edu/safety/tornadoguide.html