Seven tornadoes were confirmed in north central Illinois in the NWS Chicago CWA.  Six of the tornadoes formed from a single supercell. The atmosphere was ripe for severe weather due to highly anomalous moisture and instability for early April across the region.  A strong low pressure system advanced into this favorable air mass. Combined with robust wind shear, this helped to trigger these potent storms.  A long tracked violent tornado destroyed numerous homes and farmsteads along its path across north central Lee, eastern Ogle, northwest Dekalb, and southern Boone counties.  This path included the far northwest side of Rochelle, Interstate-39, and a direct hit in the community of Fairdale where two fatalities occurred.  This was the strongest tornado in the NWS Chicago CWA since the F5 tornado that struck Plainfield, IL on August 28th, 1990.

Tornado in WINNEBAGO, ILLINOIS
From 09-APR-15 17:37:00 to 09-APR-15 17:38:00 (CST-6)
Location: CHERRY VLY
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

An emergency manager and trained spotters photographed a tornado that touched down south of Cherry Valley.  The tornado did not produce any damage.  The tornado continued into Boone County. (Tornado 1a of 7).

Tornado in DE KALB, ILLINOIS
From 09-APR-15 18:15:00 to 09-APR-15 18:17:00 (CST-6)
Location: FAIRDALE
Tornado F-scale: EF1
Property damage: 5.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This tornado was identified from a storm chaser video and survey.  Heavy damage to two small outbuildings occurred on Paulson Road.  Maximum winds speeds were estimated to be 110 mph.  The tornado continued into Boone County. (Tornado 4a of 7).

Tornado in BOONE, ILLINOIS
From 09-APR-15 18:17:00 to 09-APR-15 18:21:00 (CST-6)
Location: IRENE
Tornado F-scale: EF1
Property damage: 75.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This is a continuation of a tornado that began in Dekalb County.  This tornado was identified from a storm chaser video and survey.  Three barns were destroyed on Pearl Street Road.  Maximum winds speeds were estimated to be 110 mph. (Tornado 4b of 7).

Tornado in BOONE, ILLINOIS
From 09-APR-15 18:24:00 to 09-APR-15 18:25:00 (CST-6)
Location: BELVIDERE
Tornado F-scale: EF0
Property damage: 20.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This was a satellite tornado that formed from the same storm that formed the long tracked EF-4 tornado.  A small zoo was heavily damaged with walls collapsed on several outbuildings and small barns.  Three animals were killed.  Softwood trees 4 to 6 inches in diameter were snapped.  The estimated peak wind was 85 mph.  (Tornado 5 of 7).

Tornado in BOONE, ILLINOIS
From 09-APR-15 18:25:00 to 09-APR-15 18:31:00 (CST-6)
Location: HERBERT
Tornado F-scale: EF1
Property damage: 150.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Witnesses said the tornado touched down in a field then moved northeast destroying a detached garage.  The tornado ripped the roof off of a home though the walls mainly remained intact.  Several hardwood trees were snapped.  Maximum wind speeds were estimated to be 110 mph.  (Tornado 6 of 7).

Tornado in MCHENRY, ILLINOIS
From 09-APR-15 18:50:00 to 09-APR-15 18:51:00 (CST-6)
Location: HARTLAND
Tornado F-scale: EF1
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A brief tornado snapped and uprooted 6 to 7 trees at a property on McGuire Road southeast of Harvard.  Minor tree damage occurred on the north side of the road before ending.  Maximum winds were estimated to 90 mph.  (Tornado 7 of 7).

Tornado in LEE, ILLINOIS
From 09-APR-15 17:39:00 to 09-APR-15 17:43:00 (CST-6)
Location: FRANKLIN GROVE
Tornado F-scale: EF1
Property damage: 1.00M
Crop damage: 0.00K
Reported by: NWS Storm Survey

This is the beginning of the Rochelle-Fairdale EF-4 tornado.  At its strongest, peak winds were estimated to be 200 mph.  The tornado touched down just northeast of Franklin Grove.  A large sheet metal building on IL-38 collapsed with failure of column anchorage.  Several smaller sheet metal buildings were destroyed along E Gurler Road. Peak winds in Lee County were estimated to 110 mph.  The tornado continued into Ogle County.  (Tornado 2a of 7).

Tornado in OGLE, ILLINOIS
From 09-APR-15 17:43:00 to 09-APR-15 18:12:00 (CST-6)
Location: CARTHAGE
Tornado F-scale: EF4
Property damage: 10.00M
Crop damage: 0.00K
Reported by: NWS Storm Survey

This is the second segment of the Rochelle-Fairdale EF-4 tornado.  At its strongest, peak winds were estimated to be 200 mph which occurred during this segment of the storm.  The tornado entered Ogle County just west of IL-38 and moved northeast where it ripped the roof off of a small barn.  A neighborhood was hit on S Skare Court where damage was consistent with EF-3.  Some of the homes had large sections of the roofs ripped off while some less well constructed homes (nails instead of bolts) had collapsed walls.  The tornado continued northeast and intensified to EF-4 where several well constructed homes along South Richard Road and East Kuehl Court were completely destroyed with the slab swept clean.  Several outbuildings were destroyed along East Hemstock Road and South Center Road.  A residence on East Bethal Road received heavy damage with most of the outer walls collapsing.  The tornado once again intensified to EF-4  near IL-251 and IL-64 where well constructed homes were swept clean off their foundation.  A farmstead just northeast of the aforementioned intersection was also swept clean to the foundation.  A heavy barn was thrown and rolled on East Lindenwood Road.  In total, around 30 homes were damaged or destroyed around Rochelle.  The tornado continued into Dekalb County just north of East Quarry Road.  (Tornado 2b of 7).

Tornado in DE KALB, ILLINOIS
From 09-APR-15 18:12:00 to 09-APR-15 18:19:00 (CST-6)
Location: FAIRDALE
Tornado F-scale: EF3
Property damage: 8.00M
Crop damage: 0.00K
Reported by: NWS Storm Survey

This is the third segment of the Rochelle-Fairdale EF-4 tornado.  At its strongest, peak winds were estimated to be 200 mph.  The tornado entered the county just southwest of Fairdale before directly hitting the small community.  Peak winds were estimated at 165 mph in Dekalb County, rating this section of the tornado a high end EF-3.  Approximately 71 homes in the community had been damaged, 17 of which had been completely destroyed with all walls collapsed or removed from the buildings.  Some homes that were only nailed to the foundation were swept clean.  Two fatalities and 11 injuries occurred in Fairdale.  A 67-year-old woman and her neighbor, a 69-year-old woman, were both killed in their homes.  The tornado began to shift north (left) at this point during its lifecycle as it left Fairdale.  Several homes were heavily damaged with large sections of the roofs removed along Wheeler road and dozens of trees were snapped and uprooted.  A few trees were debarked.  The second story was ripped off of a home near the intersection of McNeal Road and Irene Road.  A two-story rebar reinforced cinder block silo was destroyed.  The tornado continued into Boone County just east of Irene Road.  (Tornado 2c of 7).

Tornado in BOONE, ILLINOIS
From 09-APR-15 18:19:00 to 09-APR-15 18:20:00 (CST-6)
Location: IRENE
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This is the fourth segment of the Rochelle-Fairdale EF-4 tornado.  At its strongest, peak winds were estimated to be 200 mph.  The tornado entered Boone County just east of Irene Road.  No damage occurred and the tornado lifted shortly after entering the county.  (Tornado 2d of 7).

Thunderstorm Wind in GRUNDY, ILLINOIS
From 09-APR-15 19:59:00 to 09-APR-15 19:59:00 (CST-6)
Location: COAL CITY
Magnitude: 54.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Hail in MCHENRY, ILLINOIS
From 09-APR-15 17:56:00 to 09-APR-15 17:56:00 (CST-6)
Location: LAKE IN THE HILLS
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MCHENRY, ILLINOIS
From 09-APR-15 17:58:00 to 09-APR-15 17:58:00 (CST-6)
Location: CRYSTAL LAKE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in LA SALLE, ILLINOIS
From 09-APR-15 19:15:00 to 09-APR-15 19:15:00 (CST-6)
Location: LOSTANT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MCHENRY, ILLINOIS
From 09-APR-15 19:15:00 to 09-APR-15 19:27:00 (CST-6)
Location: MC CULLOM LAKE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in FORD, ILLINOIS
From 09-APR-15 20:43:00 to 09-APR-15 20:43:00 (CST-6)
Location: PAXTON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Tornado in BOONE, ILLINOIS
From 09-APR-15 17:38:00 to 09-APR-15 17:40:00 (CST-6)
Location: CHERRY VLY
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

This is a continuation of a tornado that began in Winnebago County.  An emergency manager and trained spotters photographed a tornado that touched down south of Cherry Valley.  The tornado did not produce any damage. (Tornado 1b of 7).

Tornado in OGLE, ILLINOIS
From 09-APR-15 18:05:00 to 09-APR-15 18:08:00 (CST-6)
Location: LINDENWOOD
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A brief satellite tornado formed over far eastern Ogle County.  The tornado was confirmed during an aerial survey. (Tornado 3 of 7).

Hail in MCHENRY, ILLINOIS
From 09-APR-15 19:15:00 to 09-APR-15 19:20:00 (CST-6)
Location: WOODSTOCK
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in LA SALLE, ILLINOIS
From 09-APR-15 19:15:00 to 09-APR-15 19:15:00 (CST-6)
Location: LOSTANT
Magnitude: 61.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in WILL, ILLINOIS
From 09-APR-15 20:23:00 to 09-APR-15 20:23:00 (CST-6)
Location: CHANNAHON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in LEE, ILLINOIS
From 09-APR-15 17:23:00 to 09-APR-15 17:30:00 (CST-6)
Location: DIXON MUNI ARPT
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Quarter to golf ball size hail was reported near Dixon.

Hail in LEE, ILLINOIS
From 09-APR-15 17:32:00 to 09-APR-15 17:40:00 (CST-6)
Location: FRANKLIN GROVE
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in OGLE, ILLINOIS
From 09-APR-15 17:45:00 to 09-APR-15 17:45:00 (CST-6)
Location: MT MORRIS
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in COOK, ILLINOIS
From 09-APR-15 17:45:00 to 09-APR-15 17:45:00 (CST-6)
Location: INVERNESS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MCHENRY, ILLINOIS
From 09-APR-15 17:50:00 to 09-APR-15 17:50:00 (CST-6)
Location: HUNTLEY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in BOONE, ILLINOIS
From 09-APR-15 18:04:00 to 09-APR-15 18:04:00 (CST-6)
Location: CAPRON
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

Hail in WINNEBAGO, ILLINOIS
From 09-APR-15 18:25:00 to 09-APR-15 18:25:00 (CST-6)
Location: CHERRY VLY
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MCHENRY, ILLINOIS
From 09-APR-15 19:08:00 to 09-APR-15 19:08:00 (CST-6)
Location: UNION
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter