As of December 11, 2013 the last known tornadoes were in Florida and North Carolina on November 26. The Florida tornado was an EF1 while the one in NC was an EF2.
There do not appear to be any records of tornadoes hitting Greensboro. In any given year most towns will not be hit by a tornado.
Cumulus clouds don't so much appear in tornadoes. It is more accurate to say that tornadoes descend from cumulonimbus clouds.
Tornadoes happen in both hemispheres.
No. Most tornadoes last no more than a few minutes.
Yes. Some tornadoes may last for more than an hour, but such cases are rare. Most tornadoes do not last more than 10 minutes.
in storm lake
Although they can last longer most weak tornadoes last less than 5 minutes.
Generally stronger tornadoes last longer, though this is not always they case.
Weak tornadoes typically last less than 5 minutes.
Tornadoes can occur just about anywhere in the U.S. but are most common on the Great Plains and in Florida.
Tornadoes are both much larger than tornadoes and last much longer.
Tornadoes do not always appear black. The apparent color depends on lighting conditions and how much and what color of soil is being lifted. Many tornadoes appear dark because of perspective: the are lit from behind and are essentially silhouetted against the light source. The same tornado may appear lighter if viewed from a different angle. The storms that spawn tornadoes have very thick clouds that often making conditions appear very dark. The clouds themselves may be black. Some tornadoes may be black as they lift large amounts of black soil into the air.