Local News

2015 A Record Year For Tornadoes In Chicago Area

August 28, 2015 / 11:06 AM CDT / CBS Chicago

CHICAGO (CBS) -- The Chicago area has set a record for the most tornadoes in a single year, according to National Weather Service data.

Four tornadoes on Aug. 18 brought the total for 2015 to 29, breaking the 2004 mark of 27.

The NWS data goes back to 1950.

One key factor in the increase in the number is due to better detection of weaker (EF 0, EF 1) storms through the use of more trained spotters and improved weather radar technology.

"That being said, 2015 has been an exceptionally active year for tornadoes in the Chicago forecast area," the NWS said in a statement.

One other curious bit of data: All of the tornadoes in 2014 (18) occurred on a single day, June 30.

The Top 10 List

Rank	Year	Number
1	2015	29
2	2004	27
3	1974	22
3	2010	22
4	1965	21
5	2003	18
5	2008	18
5	2011	18
5	2014	18*
10	1967	17
10	1972	17
10	2013	17

*All On June 30, 2014

The average annual number of tornadoes since 1950 is nine, the NWS said.

Since the NWS added an enhanced Doppler radar in 1992, the annual average has increased to 11.

This week also marks the 25th anniversary of one of the deadliest tornadoes in Chicago. The EF-5 that hit Plainfield killed 29 people and left widespread destruction.

The reporting area includes: Boone, Cook, DeKalb, DuPage, Ford, Grundy, Iroquois, Kane, Kankakee, Kendall, Lake, LaSalle, Lee, Livingston, McHenry, Ogle, Will and Winnebago counties in Illinois. Also, it includes, Lake, Porter, Newton, Benton and Jasper counties in Indiana.

National Weather Service