Tornadoes · United States · Illinois

Tornadoes in McHenry County, Illinois

30 tornadoes have crossed McHenry County since 1950, 52nd of the 102 counties in Illinois with a tornado on record, an average of one every 2.5 years. They have killed 32 people and injured 637. 3 were rated F4 or EF4 and above.

The rating scale

Tracks are drawn in the color of the rating. The United States rated tornadoes on Ted Fujita’s F scale until 31 January 2007 and on the Enhanced Fujita scale after it. Both run from 0 to 5, and both rate the damage rather than measure the wind: the speeds are what that damage is taken to imply.

  1. F0 / EF040 to 72 mph on the F scale, 65 to 85 mph on the EF scale

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. F1 / EF173 to 112 mph on the F scale, 86 to 110 mph on the EF scale

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. F2 / EF2113 to 157 mph on the F scale, 111 to 135 mph on the EF scale

    Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

  4. F3 / EF3158 to 206 mph on the F scale, 136 to 165 mph on the EF scale

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. F4 / EF4207 to 260 mph on the F scale, 166 to 200 mph on the EF scale

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. F5 / EF5261 to 318 mph on the F scale, over 200 mph on the EF scale

    Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

  7. Unrated

    The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

Now

Tornadoes
30
Deaths
32
Injuries
637
F4 and above
3
Worst on record
F4, April 21, 1967

The deadliest in McHenry County

  1. F4, Boone and McHenry counties, IllinoisApril 21, 196724 killed, 450 injured
  2. F4, McHenry and Lake counties, IllinoisApril 11, 19656 killed, 75 injured
  3. F4, McHenry and Lake counties, IllinoisApril 21, 19671 killed, 100 injured
  4. F2, Stephenson, Winnebago, Boone and McHenry counties, IllinoisOctober 8, 19581 killed

The strongest

  1. F4, Boone and McHenry counties, IllinoisApril 21, 1967F4, 25.5 mi (41 km)
  2. F4, McHenry and Lake counties, IllinoisApril 11, 1965F4, 9.1 mi (15 km)
  3. F4, McHenry and Lake counties, IllinoisApril 21, 1967F4, 8.8 mi (14 km)
  4. EF3, Boone and McHenry counties, IllinoisJanuary 7, 2008EF3, 13.1 mi (21 km)
  5. F2, Stephenson, Winnebago, Boone and McHenry counties, IllinoisOctober 8, 1958F2, 81.0 mi (130 km)
  6. EF2, Boone, Winnebago and McHenry counties, IllinoisNovember 22, 2010EF2, 18.1 mi (29 km)
  7. F2, McHenry County, IllinoisAugust 15, 1978F2, 2.0 mi (3 km)
  8. F2, McHenry County, IllinoisOctober 8, 1959F2, 2.0 mi (3 km)
  9. F2, McHenry County, IllinoisApril 19, 1963F2, 0.1 mi (0 km)

Every year with a tornado

The 21 years of the 76 in the record with a tornado in McHenry County. Each year links to every tornado in Illinois that year.

YearTornadoesDeathsInjuriesStrongest
20241EF0
20233EF1
20211EF1
20201EF1
20171EF1
20153EF1
201026EF2
20091EF1
200815EF3
20041F0
19961F1
19933F0
19911F0
19861F0
19781F2
19732F0
1967225550F4
19651675F4
19631F2
195911F2
195811F2

Every tornado that crossed McHenry County

30 tornadoes, newest first.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 7, 20242:05 PM CDTEF0Boone to WI14.350$60,000
July 12, 20236:33 PM CDTEF0McHenry3.4125
July 12, 20236:06 PM CDTEF1McHenry6.4200
May 31, 20233:50 PM CDTUnratedMcHenry0.625
August 9, 20214:45 PM CDTEF1McHenry0.470
August 10, 20203:05 PM CDTEF1McHenry5.7200
May 17, 201710:21 PM CDTEF1Boone10.3100$100,000
July 18, 20152:38 PM CDTEF0McHenry0.150
July 18, 20152:19 PM CDTEF0McHenry0.150
April 9, 20157:50 PM CDTEF1McHenry0.330
November 22, 20103:31 PM CSTEF1Walworth to WI5.5100$1.0 million
November 22, 20103:00 PM CSTEF2Boone18.12006$5.0 million
June 19, 20097:10 PM CDTEF1McHenry0.775$75,000
January 7, 20083:30 PM CSTEF3Boone13.11005$4.0 million
August 24, 20047:10 PM CDTF0McHenry0.820$30,000
May 19, 199612:00 AM CDTF1McHenry0.850
July 2, 19936:49 PM CDTF0McHenry0.520
June 26, 19935:35 PM CDTF0McHenry0.220$5,000 to $50,000
June 8, 19937:47 PM CDTF0McHenry0.220
April 29, 19918:30 PM CDTF0McHenry0.120
July 6, 19867:20 PM CDTF0McHenry12.010
August 15, 19788:45 PM CDTF2McHenry2.0100$50,000 to $500,000
June 16, 19732:25 PM CDTF0McHenry0.110
June 15, 19735:00 PM CDTF0McHenry0.110
April 21, 19675:00 PM GMT-6F4McHenry8.81501100$500,000 to $5 million
April 21, 19673:50 PM GMT-6F4Boone25.51,20024450$50,000 to $500,000
April 11, 19653:20 PM GMT-6F4McHenry9.1400675
April 19, 19635:45 PM GMT-6F2McHenry0.110$50,000 to $500,000
October 8, 19594:30 PM GMT-5F2McHenry2.0901$50,000 to $500,000
October 8, 195812:30 AM GMT-5F2Stephenson81.0101$500,000 to $5 million

Nearby

Warnings in force in McHenry CountyThe forecast for McHenry CountyThe live radar over McHenry CountyEvery county in Illinois

What this means

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

Sources

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.