Published: August 29,2015
29 tornadoes in NWS Chicago CWA in 2015, most tornadoes in yr on record in CWA. http://1.usa.gov/1Lziu1q #ilwx #inwx
According to the National Weather Service out of Chicago,
Illinois, their county warning area that serves north-central and
northeastern Illinois has seen more tornadoes so far in 2015 than in any
other year. Such official records for the area date back to 1950.
(MORE: 2015 Early Season Tornado Outbreak Affects Illinois)
The
severe weather season in northern Illinois typically doesn’t start
heating up until late April, and the season generally peaks in June, but
this year it started fast and furious.
An
unusually strong early spring storm system moved into the Midwest on
Apr. 9, 2015. A northward push of humid, unstable air collided with
cool, dry air draining down from the Plains. The perfect recipe for an
early season tornado outbreak.
Radar image of a tornado-producing supercell thunderstorm on the night of Apr. 9, 2015, near Rochelle, Illinois.The result was 14 tornadoes across the central U.S. that day, seven of which tore through northern Illinois. One of them was an EF-4 on the Enhanced Fujita Scale, which caused extensive damage in Rochelle, Illinois and surrounding areas. That EF-4 remains the strongest tornado reported in the U.S. so far in 2015.
This was also the third earliest violent tornado (EF-4 or stronger) on record for the greater Chicago
area, dating back to 1896, as it moved through Ogle and DeKalb
counties. Not only was it the strongest tornado on record for those
counties, but it was the single strongest tornado near Chicago in 25 years. An F-5 tornado struck Plainfield, Illinois on Aug. 28, 1990.
25 yrs ago, devastating F-5 Plainfield #tornado touched down. http://www.weather.gov/lot/Plainfield_Tornado_Anniversary … https://business.facebook.com/NWSChicago/posts/966307870092914 … #ilwx
The tornado season
remained fairly quiet for over two months through much of May and June,
until the next tornado outbreak hit northern Illinois June 22 with 12
tornadoes, right in the heart of Illinois’ severe weather season.
The Chicago
National Weather Service says that one long-lived supercell
thunderstorm single handedly produced 10 tornadoes in that event. Lee
County saw three of those tornadoes, the most the county has seen on one
calendar day, dating back to 1950. The strongest was another significant (EF-2 or stronger) tornado, an EF-3 in Coal City, Illinois.
A view of a flooded street and damaged homes after a #tornado struck the previous day on June 23, 2015 in Coal City…
Local residents
know tornado damage all too well, as a destructive EF-2 tornado struck
Coal City less than two years earlier during the Nov. 17, 2013 severe
weather outbreak.
(MORE: Interactive Map of the Midwest Tornado Outbreak of Nov. 17, 2013)
Two single tornado outbreaks in 2015 have accounted for 26 of the 29 tornadoes confirmed in the Chicago
area. This goes to show that even in a seemingly quiet severe weather
season, just one or two outbreaks can wreak a lot of havoc. Just ask
residents of Illinois about 2013, a record quiet tornado season that
featured a historic tornado outbreak in November, of all months.
(FORECAST: Chicago | Rockford)
While
it is tough to say if the area will see any more tornadoes this year,
tornadoes have hit Illinois in all 12 months of the year. Even if there
is not another tornado in the area this year, 2015 goes down as the year
with the most tornadoes in the greater Chicago area.
Are Tornadoes Becoming More Common?
Although the number of all tornadoes in the Chicago
area has been apparently climbing over the years, that does not mean
that more tornadoes are occurring. Radar technology, which continues to
improve, makes it easier to identify where tornadoes may have touched
down, even if they strike in an isolated area, such as within a deep
forest. Social media may also play a role in confirming tornadoes, as it
is easier for people to share reports of such storms.
It's
also tough to make a conclusion on tornado frequency based on variation
in the tornado records. Although the trend of all tornadoes shows an
apparent increase in tornadoes over the past decade near Chicago, that may be skewed by a period of inactive tornado seasons from 1996 to 2002.
Counts of all tornadoes and all EF-2+ tornadoes in the NWS Chicago county warning area. (Courtesy: NWS Chicago)When looking at the Chicago area number of EF-2 and stronger tornadoes, the linear trend is actually decreasing. Yet again, the data may be a bit skewed since the 1960s and 1970s had several significant tornadoes, but then there was a period of very few such events from the 1980s to early 2000s.
Nationally,
this year is trending to be the fourth year in a row of below average
number of tornadoes. The bottom line is that there is no clear
indication that tornadoes are becoming more or less common, in the Chicago area, or anywhere across the U.S. for that matter.
MORE: Worst Fall Tornado Outbreaks (PHOTOS)
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