June 20-21, 2021: Late Night Tornadoes and Wind Damage, Including an EF-3 Tornado From Naperville to Willow Springs (2024)

Fast Facts:

Summary:

During the late evening of Sunday, June 20, 2021 and into theearly overnight hours onMonday, June 21, storms increased in intensity rapidly as they moved toward and into the Chicago metropolitan area, producingdamaging winds and fourtornadoes.

The most significant damage impactedsouthwest suburbs of Naperville, Woodridge,Darien, Burr Ridge, and Willow Springsbetween 11:00 and 11:25pm, where an EF-3 tornado damaged over 900structures (including at least 300 that suffered significant damage or were destroyed), downed thousands of trees, and caused at least 11 injuries.

The Naperville to Willow Springs tornado wasthe first significanttornado (rating ofEF-2 or greater) to occur in the NWS Chicago County Warning Areasince February 28, 2017 (Naplate/Ottawa), and the firstEF-2+ tornado to occurin the Chicago metro counties since June 22, 2015 (Coal City). A list of EF-2+ tornadoes in the Chicago metro can be found here. This is accessible on our tornado climatology for the area here.

The EF-3 tornado historical perspective

An EF-0 tornado with peak winds of 85 mph and a path length of 4.8milestouched down near downtownPlainfield and lifted in northwest Crest Hill. Tree damage was common along the path of the tornado.

A second EF-0 tornado with peak winds of 75 mph and a path length of 3.3 miles touched down near South Haven, Indiana and caused primarily tree damage.

Another EF-0 tornado with peak winds of 70 mph and a path length of 0.4 miles was later confirmed to have occurred on the east side of Addison. This brief tornado produced sporadictree damage across its short track.

Outside of tornadoes,damage caused by strong straight-line winds was reported elsewhere across the area. An interactive map of storm reportscan be found here.

Preparedness:While there was a fairly fast-moving strong tornado in the densely populated southwest Chicago suburbs and after dark, the number of serious injuries was relatively small. This, at least in part, had to do with preparedness and people taking action when the warnings were issued. It was also a reminderofthe importance of having multiple means to receive a warning. For more on severe weather preparedness, see here.

The Forecast:

Severe Weather Outlook for Sunday issued Friday morning

Severe Weather Outlook for Sunday issued Saturday afternoon

Severe Weather Outlook for Sunday issued that morning

NWS Chicago Weather Story issued 6:00 A.M. Sunday

NWS Chicago Weather Story issued 6:30 P.M. Sunday

NWS Chicago Weather Story issued 10:00 P.M.Sunday

Severe Thunderstorm Watch issued at 9:40 P.M. Sunday evening until 2:00 A.M.

Tornado Warning issued at 10:43 P.M. that included western DuPage County and portions of Naperville

LargeSevere ThunderstormWarning issued at 10:56 P.M. that included all of southernDuPage County (this mentioned "tornado possible")

Tornado Warning issued at 11:05 P.M. for all of southern DuPage County and into western Cook County. This included mostof Naperville proper, Woodridge,Darien, Burr Ridge, and Willow Springs.

Damage Surveys / Tornadoes:

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About NWS Damage Surveys

Tornado #1: Naperville to Willow Springs EF-3

Downloadable KMZ file

Downloadable shapefile

Summary:

The approximate starting location of the tornado was just south of 75th St. on the western edge of the Springbrook Prairie Forest Preserve at 11:02 PM. The continuous damage path started near Plainfield-Naperville Road and Sheppey Court at about 11:05 PM. Sporadic wind damage was found both west and east of this point before the path became more concentrated and continuous east of Modaff Road.The tornado gradually intensified as it tracked east, and especially east of Naper Boulevard, where damage to homes became common. The tornado reached peak intensity in the area around Princeton Circle in Naperville where a house completely collapsed and multiple nearby homes also sustained considerable damage to their roof and walls. From that location, the tornado continued east across the Greene Valley Forest Preserve into Woodridge. Another area of concentrated damage occurred between Woodridge Drive and Basswood Lane in Woodridge where numerous homes lost several walls and apartment buildings lost large portions of roofing material. The tornado continued east-southeastward producing primarily tree damage from Lemont Road into southern Darien, across Interstate 55, and southern Burr Ridge. The damage path became narrow as it crossed the Des Plaines River into Willow Springs, atwhich point, the tornado dissipated near Buffalo Woods at approximately 11:25 PM CDT. In total, at least 900structures sustained some sort of damage from the tornado with at least 300 of these structures sustaining significant damage.The most significant structural damage occurred in Naperville and Woodridge, and at least 11 people suffered injuries that required medical treatment.

Tornado #2: Plainfield to Crest Hill EF-0

Downloadable KMZ file

Downloadable shapefile

Summary:

An NWS damage survey found sporadic minor tree damage consistent with straight-line winds in the vicinity of Meadow Lane between 143rd St. and Lockport St. eastward to Illinois Route 59 in Plainfield. A concentrated swath of more significant tree damage consistent with an EF-0 tornado was evident beginning near the intersection of Illinois Routes 59 and 126 just north of downtown Plainfield and extending eastward through adjacent neighborhoods. A path of minor tree damage continued east-southeast through the Lake Renwick Preserve, crossing Interstate 55 just south of Lockport Street. A path of more sporadic tree damage was found in the Fieldstone neighborhood ofRomeoville around Helen Drive, with the damage path extending across Mistwood Golf Club. The path continued southeast into northwest portions of Crest Hill, where another concentrated area of significant tree damage was observed around Rosemarie Lane. The tornado lifted in the vicinity of the intersection of Thomas Drive and Weber Road. Some areas just south of the track experienced strong straight-line winds.

Tornado #3: South Haven EF-0

Downloadable KMZ file

Downloadable shapefile

Summary:

An NWS damage survey, along with information relayed by the Porter County Emergency Management Agency, indicate a swath of straight-line wind damage extended form Hobart to the Robbinhurst Golf Club just north of South Haven. A small outbuilding was heavily damaged near the golf club, but tree damage in the area was directed entirely in an east to east-northeast direction. Damage became more concentrated in a localized area immediately east of north State Road 149 and north of West County Road 875 North where a large tree was uprooted and several residences exhibited minor shingle loss consistent with an EF-0 tornado. This tornado tracked northeast where it continued to produce sporadic damage to trees near north County Road 150 before damage ended near North Meridian Road and East County Road 950. Sporadic minor tree damage persisted east of State Road 49.

Tornado #4: Addison EF-0

Downloadable KMZ file

Downloadable shapefile

Summary:

Based on an eyewitness account and damage seen during an NWS damage survey, it was determined that a brief tornado touched down at the intersection of Lake St. and Villa Ave. in Addison and tracked southeastward for about 0.4 miles before lifting. The tornado was on the ground for less than a minute and mainly produced sporadic tree damage along its track.

The Enhanced Fujita (EF) Scale classifies tornadoes into the following categories:

EF0 Weak 65-85 mph	EF1 Moderate 86-110 mph	EF2 Significant 111-135 mph	EF3 Severe 136-165 mph	EF4 Extreme 166-200 mph	EF5 Catastrophic 200+ mph

Radar:

The EF-3 tornado that impacted Naperville, Woodridge, Darien, Burr Ridge, and Willow Springs developed quickly along the leading edge of a line of storms, sometimes known as a Quasi-Linear Convective System (QLCS).

0.5 degree base reflectivity from KLOT between 10:50 and 11:28 PM CDT

0.5 degree base velocityfrom KLOT between 10:50 and 11:28 PM CDT

As a tornado is ongoing, we can alsothe strength of windsbased on the height at which debris is lofted. Tornadoes that are considered "weak," or EF-0 to EF-1 on the Enhanced Fujita scale, rarely loft debris more than 7,000 feet into the atmosphere. Strong tornadoes, rated EF-2 or greater, often loft debris beyond 10,000 feet. The indicationof debris to nearly 20,000 feet as the Naperville to Willow Springs EF-3 tornado was ongoing confirmed that a dangerous situation was unfolding.With Dual-Polarization radar, with which we can infer the shape of reflectors to the radar beam, minima in "correlation coefficient" co-located with tight rotational velocity couplets indicates the presence of lofted debris. This is a signature that confirms the presence of a tornado. During the evening of June 20, simultaneous tornado debris signatures were present as both the Naperville toWillow Springs EF-3 and Plainfield toCrest Hill EF-0 tornadoes were occurring at the same time.

11:12 p.m.1.3 Degree Correlation Coefficient

11:17p.m. Correlation Coefficient Cross Section

As the EF-3 tornado continued past Woodridge, it displayed a "classic" tornado debris signature with a spike in reflectivity, tight rotational signature, drop in correlation coefficient values, and drop in differential reflectivity to ~0 dB. While this signature helps NWS meteorologists by confirming that a dangerous tornadois ongoing, it isneversomething that we want to see, especially in a densely populated area.

Four-panel (clockwise from top left) radar reflectivity, base velocity, differential reflectivity, and correlation coefficient at 11:14 p.m. June 20, 2021.

Finally, we tracked the tornado using data not only from our WSR-88D radar in our backyard, but also two Terminal Doppler Weather Radars (TDWRs) owned and maintainedby the FAA located near Chicago O'hare and Midway airports. In certain scanning strategies, data from both TDWRs are available every minute compared to every 2-3 minutes from our WSR-88D, providing NWS Chicago meteorologists the opportunity to track severe weather nearly as it happens.

Clockwise from top left:

0.5 degree base velocity from KLOT

0.3 degree velocity from TORD

0.3 degree velocity from TMDW

0.5 degree reflectivity from KLOT,

between 11:05 and 11:14 PM CDT June 20, 2021.

Photos:

Photos from NWS Damage Survey of Naperville-Willow Springs Tornado:

Large trees downed on Naperville Fire Station 2 (NWS Damage Survey)

Power poles downed on E Bailey Road west of Naper Blvd in Naperville (NWS Damage Survey)

Damaged car on 77th Street in Naperville(NWS Damage Survey)

Large tree uprooted and pulled along Ranchview Drive in Naperville (NWS Damage Survey)

Home completely destroyed on Princeton Circle in Naperville, garnering an EF-3 rating(NWS Damage Survey)

Damaged home on Woodridge Drivein Woodridge (NWS Damage Survey)

Damaged homes nearWoodridge Drive Woodridge (NWS Damage Survey)

Damaged homenearWoodridge Drive Woodridge (NWS Damage Survey)

Damaged home near Janes Ave in Woodridge (NWS Damage Survey)

Damaged homenearIde's Grove West Park in Woodridge (NWS Damage Survey)

Extreme tree damage near Ide's Grove West Park in Woodridge (NWS Damage Survey)

Thrown tree near Ide's Grove West Park in Woodridge (NWS Damage Survey)

Additional Photos:

Damage in Woodridge. Photo courtesy of Greg Dutra.

Damage in Naperville. Photo courtesy of Mike Smith.

Damage in Naperville. Drone footage courtesy of Greg Mulvey.

Damage near South Haven. Courtesy of the Porter County Emergency Management Agency.

Environment

On June 20, 2021, a moist, unstable, and explosive thunderstorm environment was forecast to develop over the Lower Great Lakes. Two rounds of severe weather were anticipated - the first during the early afternoon and the second after dark. The first round of thunderstorms developed in northwestern Indiana instead of Illinois, providing a sense that we were out of the woods for the rest of the day. Unfortunately, thatwasn't the case as thunderstorms erupted along an eastward-moving cold front later in the day in Iowa, which moved into northern Illinois and northwestern Indiana after dark.

2 p.m. Sunday Surface Map (hand analyzed)

One of the NWS Chicago meteorologists drew a surface analyses at about 2 pm depicting a deepening 1000 mb low pressure systemalong the IA/MN border and a surface warm front stretching eastward across the central Great Lakes. A moist (and inferred unstable) airmass was analyzed generally along and south of I-80, with light but increasing southerly winds helping transport it northward.

10 p.m. Sunday Surface Map (computer analyzed)

By 10 p.m., the surface low reached 997 mb (quite deep for summer) with increasing southerly winds. Another smaller scale ("mesoscale") low pressure was indicated across northern Illinois, likely associated with a convectively-generated vortex. This further backed surface winds and increased a tornado threat into the Chicago metropolitan area, especially with the amount of moisture. Overall, this may depictsa very favorable large scale pattern for severe weather including tornadoes.

One of the key elements to the environment was the rapid pace at which it destabilized. Earlier in the day, weakening showers and widespread cloud cover greatly limited the ability for the atmosphere to destabilize. The sun did not appear until around dinnertime, which with a developing and strong low-level jet allowed the air to rapidly become favorable for severe weather. It is not often the most unstable air of the day occurs after dark!

Loop of MLCAPE and MLCIN from approximately 4 p.m. to 11 p.m.

As the atmosphere was rapidly destabilizing, so was the low-level wind shear. By 11 p.m., model-analyzed0-1 and 0-3 km shear exceeded 30 and 35 kt, respectively, which is far sufficient for severe weather and rotating storms. The effective bulk wind shear also exceeded 40 kt, which is more than sufficient for rotating storms, too.

0-1 km shear

0-3km shear

Effective Bulk shear

Observations, however, demonstrated that the degree of wind shear was not fully captured by forecast or model-analyzed parameters. The observed wind profile from the NWS Chicago WSR-88D demonstrated extreme amounts of low-level wind shear, with 0-1 km storm-relative helicity in excess of 600 m2/s2, and 0-3 km storm-relative helicity in excess of 800 m2/s2. Typically, storm-relative helicity values in excess of 150 m2/s2is thoughtas favorable for tornadoes.

Vertical Wind Profile and Hodograph from the NWS Chicago WSR-88D around the time of the EF-3 tornado

Higher impact weather events are always worth researching and learning from. The NWS Chicago, along with others in the academic and research sectors, have dug into this event and will likely continue to in the future. Some takeaways can be found in the below 2022 American Meteorological Society (AMS) national conference poster.

Click here for pdf.

Rain Reports

Public Information StatementNational Weather Service Chicago IL940 AM CDT Mon Jun 21 2021 /1040 AM EDT Mon Jun 21 2021/...Rainfall Totals from Sunday, June 20... The following are rain amounts for the previous 24-hours as measured in the morning by NWS Cooperative Observers and CoCoRaHS observers. Observations are usually taken between 6 AND 8 AM. 24-hour rainfall amounts for Monday(06/21/21)...Illinois Rain Location (County): fall (inches) Lake Zurich (Lake)...........................2.75 Genoa (De Kalb)..............................2.69 Elk Grove Village 1ESE (Cook)................2.62 Bartlett 1SE (Du Page).......................2.44 Schaumburg 2E (Cook).........................2.42 Kingston 2WNW (De Kalb)......................2.39 Harwood Heights (Cook).......................2.38 Lake Zurich 1N (Lake)........................2.33 Ashton (Lee).................................2.31 Woodstock 4SW (McHenry)......................2.30 St. Charles (Kane)...........................2.24 Woodstock 1SSW (McHenry).....................2.19 Hoffman Estates 2SE (Cook)...................2.18 Lake Forest 2NNE (Lake)......................2.07 Buffalo Grove 2N (Lake)......................2.06 Barrington (Lake)............................2.00 Lincolnwood 2E (Cook)........................1.98 Gilberts (Kane)..............................1.97 Park Ridge 1WNW (Cook).......................1.95 Elk Grove Village 2WSW (Cook)................1.94 Highwood 1S (Lake)...........................1.94 Algonquin 1N (McHenry).......................1.92 Glencoe (Cook)...............................1.91 Lake Bluff 1W (Lake).........................1.91 Cary (McHenry)...............................1.89 Libertyville 2ESE (Lake).....................1.87 Elmwood Park 1ESE (Cook).....................1.85 Ohare Airport (Cook).........................1.85 Riverwoods (Lake)............................1.84 Elgin (Kane).................................1.82 Rogers Park 2SW (Cook).......................1.81 Schaumburg (Du Page).........................1.74 Hoffman Estates 5W (Cook)....................1.71 Park Ridge (Cook)............................1.70 Arlington Heights 1S (Cook)..................1.67 Palatine 1NNE (Cook).........................1.66 Oak Park 1NNE (Cook).........................1.64 Elgin (Kane).................................1.63 Elgin 1S (Kane)..............................1.63 St. Charles 6NW (Kane).......................1.63 Crystal Lake (McHenry).......................1.61 Mount Prospect 3NE (Cook)....................1.61 Arlington Heights 1SW (Cook).................1.60 Cortland (De Kalb)...........................1.58 Steward (Lee)................................1.56 Elgin 8WSW (Kane)............................1.55 Elgin 2W (Kane)..............................1.52 Elgin 2WNW (Kane)............................1.51 Brandon Road Lock & Dam (Will)...............1.50 New Lenox 2SE (Will).........................1.45 West Chicago (Du Page).......................1.43 Amboy (Lee)..................................1.42 Dixon (Lee)..................................1.41 DeKalb (De Kalb).............................1.40 Mundelein (Lake).............................1.40 Chicago 6NNE (Cook)..........................1.39 Villa Park 1NW (Du Page).....................1.39 Elmhurst 1ESE (Du Page)......................1.36 Bull Valley 2WNW (McHenry)...................1.36 Lake Villa 1SSW (Lake).......................1.32 Crystal Lake 1WSW (McHenry)..................1.32 Ravenswood Manor (Cook)......................1.29 Elmhurst (Du Page)...........................1.27 New Lenox 3E (Will)..........................1.26 Seneca 1NNE (La Salle).......................1.25 Sugar Grove 1ENE (Kane)......................1.24 Park Forest (Cook)...........................1.23 Crete 3E (Will)..............................1.22 Manhattan 1ESE (Will)........................1.22 Channahon 2SSE (Will)........................1.22 Park Forest 1NNE (Cook)......................1.21 Manhattan 2SE (Will).........................1.21 Sugar Grove 1NE (Kane).......................1.20 Plainfield 5SW (Kendall).....................1.19 Joliet 2n (Will).............................1.19 Countryside 1ENE (Cook)......................1.18 Mokena 1W (Will).............................1.18 Lake Villa 2WSW (Lake).......................1.17 Plainfield 2SSE (Will).......................1.17 Wheeling (Cook)..............................1.17 Aurora (Kane)................................1.16 Lockport 1SE (Will)..........................1.16 Aurora 4SE (Du Page).........................1.14 Manhattan (Will).............................1.14 Flossmoor 1ESE (Cook)........................1.13 Oregon (Ogle)................................1.12 Oswego 5SSE (Kendall)........................1.11 Paw Paw (Lee)................................1.10 Beecher 3ENE (Will)..........................1.09 North Utica 6N (La Salle)....................1.08 McHenry (Stratton Lock & Dam) (McHenry)......1.08 Earlville 3S (La Salle)......................1.07 Round Lake 2WNW (Lake).......................1.05 Mendota (La Salle)...........................1.05 Oak Park 1SW (Cook)..........................1.03 Joliet (Will)................................1.03 Elmhurst 2SE (Du Page).......................1.02 Coal City 4NNW (Grundy)......................1.01 Lemont (Cook)................................1.01 Carbon Hill 3.1N (Grundy)....................1.01 Homewood (Cook)..............................1.00 Earlville 5NNE (De Kalb).....................1.00 Morris (Grundy)..............................0.97 Coal City 3N (Grundy)........................0.96 North Aurora 2NE (Kane)......................0.96 Morris 6ESE (Grundy).........................0.95 Woodstock 5nw (McHenry)......................0.95 Bolingbrook 3NE (Du Page)....................0.94 Peotone (Will)...............................0.93 Romeoville (Will)............................0.93 Peotone (Will)...............................0.93 Oak Park 2S (Cook)...........................0.92 Naperville 4SSW (Will).......................0.92 Midway (Cook)................................0.92 Midway Coop (Cook)...........................0.92 Midlothian (Cook)............................0.91 Montgomery 1SSE (Kendall)....................0.91 Palos Park 1SW (Cook)........................0.88 Geneva 4WSW (Kane)...........................0.88 Ottawa 2N (La Salle).........................0.88 Plano (Kendall)..............................0.87 Morris 2SSE (Grundy).........................0.85 Batavia (Kane)...............................0.84 Hebron (McHenry).............................0.83 Lombard 1NNW (Du Page).......................0.83 Geneva 1SSW (Kane)...........................0.83 Bridgeview 1NNW (Cook).......................0.82 Chicago Ridge (Cook).........................0.81 Dixon 3NNW (Lee).............................0.81 Oak Lawn (Cook)..............................0.80 Ottawa (La Salle)............................0.80 Wonder Lake 1NE (McHenry)....................0.79 Mendota (La Salle)...........................0.78 Beecher 3SSE (Will)..........................0.77 Wheaton 2NNE (Du Page).......................0.75 Wilmington 6NW (Will)........................0.75 Waukegan (Lake)..............................0.75 Westmont 1SSW (Du Page)......................0.74 Lisle (Du Page)..............................0.74 Harvard 3SSE (McHenry).......................0.74 Oak Lawn 2SE (Cook)..........................0.71 Burr Ridge 2SW (Du Page).....................0.71 Oak Lawn 2WNW (Cook).........................0.70 Ottawa 1NW (La Salle)........................0.70 Channahon 1NNE (Will)........................0.69 Aurora (Kane)................................0.68 Chicago 6ESE (Cook)..........................0.68 La Salle (La Salle)..........................0.67 Ottawa (La Salle)............................0.67 Winthrop Harbor 1SSW (Lake)..................0.65 Lisle Morton Arb (Du Page)...................0.65 Glen Ellyn 1WSW (Du Page)....................0.64 Morris 5NNW (Grundy).........................0.64 Peru 1ENE (La Salle).........................0.64 Westmont (Du Page)...........................0.64 Romeoville (Will)............................0.62 Harvard (McHenry)............................0.60 Zion (Lake)..................................0.60 Gurnee 2W (Lake).............................0.60 Rockford (Winnebago).........................0.60 Capron (Boone)...............................0.55 Bourbonnais (Kankakee).......................0.45 Peru (La Salle)..............................0.45 Dwight (Livingston)..........................0.27 St Anne (Kankakee)...........................0.27 Watseka 6.9WNW (Iroquois)....................0.26 Chatsworth (Livingston)......................0.25 Darien (Du Page).............................0.25 Herscher 3E (Kankakee).......................0.20 Emington 2SSE (Livingston)...................0.20 Chebanse (Kankakee)..........................0.17 Pontiac (Livingston).........................0.17 Kankakee (Kankakee)..........................0.14 Ashkum 5.6E (Iroquois).......................0.10 Buckley (Iroquois)...........................0.06 Gibson 6NE (Ford)............................0.04 Cissna Park 1S (Iroquois)....................0.02 Gibson 3WNW (Ford)...........................0.01Indiana Rain Location (County): fall (inches) Lakes Of The Four Seasons (Porter)...........1.63 Crown Point (Lake)...........................1.40 Crown Point 1N (Lake)........................1.40 Schererville 1E (Lake).......................1.30 Schererville 1E (Lake).......................1.29 Valparaiso 1SE (Porter)......................1.24 St. John (Lake)..............................1.22 Valparaiso 1NNW (Porter).....................1.14 Valparaiso 1NE (Porter)......................1.11 Valparaiso 4SW (Porter)......................1.05 Griffith 1N (Lake)...........................1.00 De Motte 1NNW (Jasper).......................0.98 Valparaiso 6SSW (Porter).....................0.91 Valparaiso (Porter)..........................0.89 Valparaiso 2WNW (Porter).....................0.82 Wheatfield 3S (Jasper).......................0.72 De Motte 4SW (Jasper)........................0.69 Hammond 1SSW (Lake)..........................0.64 Gary 5ENE (Lake).............................0.58 Brook 4W (Newton)............................0.57 De Motte 6S (Jasper).........................0.55 Rensselaer (Jasper)..........................0.54 Portage 3E (Porter)..........................0.53 Rensselaer 10NNE (Jasper)....................0.48 Porter 1S (Porter)...........................0.48 Chesterton 1ENE (Porter).....................0.47 Kentland (Newton)............................0.46 Remington (Jasper)...........................0.40 Rensselaer 2SSW (Jasper).....................0.35 Kentland 2SSE (Newton).......................0.30 Rensselaer 5NW (Jasper)......................0.15 Mount Ayr 2NNE (Newton)......................0.15 Rensselaer 4N (Jasper).......................0.11

Other NWS Office Recaps

Central Iowa (NWS Des Moines)
Eastern Iowa and Northwest Illinois (NWS Quad Cities)
Northern Indiana (NWS Northern Indiana)
National Summary (NWS Storm Prediction Center)
NWS Chicago Past Events Page