February tornadoes are rare but violent
Harrisburg, Illinois was struck by a deadly tornado on Feb. 29, leading to six reported deaths and widespread damage. While more common during spring and summer in Illinois, tornadoes sometimes occur in February, said Illinois State Climatologist Jim Angel of the Illinois State Water Survey, University of Illinois at Urbana-Champaign.
Out of 2,320 tornadoes reported in Illinois between 1950 and 2011, 39 of them have occurred in February. However, this small number caused 6 deaths and 28 serious injuries. With this latest event, we have doubled the number of tornado-related deaths in February since 1950.
The National Weather Service has identified the Harrisburg tornado as an EF-4 event with wind speeds up to 170 mph. The EF stands for the enhanced Fujita scale which uses the level of destruction to estimate wind speeds.
EF-4 tornadoes are relatively rare in Illinois. Out of 2,320 tornadoes reported in Illinois between 1950 and 2011, only 40 were in this category. However, they are very deadly. Of the 203 tornado-related deaths during that same period, 49 percent or 100 deaths came from EF-4 events. That is an average rate of 2.5 deaths per EF-4 event.
Before Harrisburg, the only other EF-4 tornadoes to strike Illinois in February was on February 25, 1956 when one passed south of St. Louis and into St. Clair County Illinois, causing 6 deaths in those two states.
The Harrisburg event is the worst tornado disaster in Illinois since the 2004 Utica EF-3 tornado that killed 8 people. Southern Illinois is home to the worst tornado disaster in U.S. history. On March 18, 1925, the infamous Tri-State Tornado caused 695 deaths as it moved through southeast Missouri, southern Illinois, and southern Indiana.
“Be prepared for severe weather,” says Angel. “Stay informed about a tornado warning through a weather alert radio, the local media, the web, or smartphone apps. Have a plan for seeking shelter at home, work, school, or while you travel.”
The Illinois State Water Survey at the University of Illinois at Urbana-Champaign, a division of the Prairie Research Institute, is the primary agency in Illinois concerned with water and atmospheric resources.