The answer depends on where you find the information.
The NOAA website lists an average of 28 tornadoes per year for South Dakota.
The US Tornadoes website list an average of 36 tornadoes per year for South Dakota.
On average, South Dakota experiences around 30 tornadoes per year. These tornadoes can range from weak to strong in intensity and typically occur during the spring and summer months. Tornadoes in South Dakota are also more common in the eastern part of the state.
It depends on which tornado you are referring to. South Dakota has had many tornadoes. Most have not been killers but some have been. So far in 2010, however, the have been no tornado fatalities in South Dakota.
There were 94 tornadoes in Alabama in 2008.
15 tornadoes occurred in Michigan in 2011.
There were 105 tornadoes in Iowa in 2008.
There were 1,103 tornadoes in the U.S. in 2006.
There were 20 tornadoes in Ohio in 2014.
There were 16 confirmed tornadoes in Arkansas in 2007.
There were 1,817 tornadoes recorded in the U.S. in 2004.
The U.S. had 1075 confirmed tornadoes in 2000.
65 tornadoes occurred in North Carolina in 2011.
There were 1374 tornadoes confirmed in the United States in 2003.