Tornado climatology
The United States averaged 1,274 tornadoes per year in the last decade. April 2011 saw the most tornadoes ever recorded for any month in the US National Weather Service's history, 875; the previous record was 542 in one month. It has more tornadoes yearly than any other country and reports more violent (F4 and F5) tornadoes than anywhere else.
Tornadoes in the United States
Of the states around the Rocky Mountains, Colorado reports by far the greatest numbers of tornadoes. Eastern Colorado, both climatically and physically, has much more in common with the neighboring Plains states of Kansas and Nebraska than with the mountainous areas further west. Small cities such as Limon, Kit Carson, Thurman, and Flagler are some places in Eastern Colorado that have experienced dangerous tornadoes. The same can be said, to a lesser extent, of eastern Wyoming. Tornadoes are less frequent in mountainous areas. Of the states in this region – according to NCDC figures for the 1950 to 2006 period – Colorado reported 1,617 tornadoes, followed by Wyoming with 560, Montana (345), Idaho (175), and Utah (114).