It varies from year to year, but on average California gets 11 tornadoes annually.
The U.S. had 1282 tornadoes in 2010.
There were 1692 confirmed tornadoes last year of which at least 1492 caused some damage.
On averages there are 11 tornadoes in California a year.
There were 1692 confirmed tornadoes in the U.S. in 2011.
As of November 30, 2012 the last confirmed tornado in California was on November 9.
Tornadoes happen in both northern and southern California.
Since official record began in 1950, California has had 404 recorded tornadoes up through the year 2013. The actual number of tornadoes is likely much higher, as many of the less intense tornadoes went without being recorded.
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.
There were 1156 confirmed tornadoes in the U.S. in 2009.
About 30 tornadoes per year.
In the latest five-year period (not counting 2011 as statistics are not finalized) the U.S. experienced 6329 tornadoes.