The map below, compiled by John Nelson from NOAA data shows where tornados have occurred in the United States during the period 1950 through 2006. Each line tracks an individual tornado and the brightness of the color denotes strength.
The bar graph records the number of injuries (blue) and deaths (green). To get a better look at the map go to this link. There you will find a high-definition map that you can click to focus on specific areas. Check out the tornados in Arizona.
See the full story at WUWT here.