Tornadoes · United States · Michigan · 1991
F3 tornado, Calhoun County, Michigan, March 27, 1991
This F3 tornado ran 2.0 miles across Calhoun County on March 27, 1991, touching down at 7:00 PM EST and reaching 400 yards wide. It killed nobody and injured 18, and did $50,000 to $500,000 of property damage.
The rating scale
Tracks are drawn in the color of the rating. The Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.
F040 to 72 mph
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
F173 to 112 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
F2113 to 157 mph
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.
F3158 to 206 mphthis tornado
Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.
F4207 to 260 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
F5261 to 318 mph
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.
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.
The record
- Rating
- F3
- Date
- March 27, 1991
- Touchdown
- 7:00 PM EST (00:00 UTC)
- Path length
- 2.0 miles (3.2 km)
- Path width
- 400 yards (366 m)
- Deaths
- 0
- Injuries
- 18
- Property damage
- $50,000 to $500,000
- County
- Calhoun County
- Touchdown point
- 42.380, -84.900
- Record number
- 167
The warnings
No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 09:43 UTC | 10:05 UTC | Severe Thunderstorm Warning | GRR |
| 00:24 UTC | 01:30 UTC | Severe Thunderstorm Warning | GRR |
Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.
The forecast that day
The Storm Prediction Center had this point in a High Risk. The outlook in force was issued at 07:20 UTC.
SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.
The air that afternoon
The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.
Detroit, MI (KFNT), 00:00Z
0.0 hours before the tornado, 126 km from the path. March 28, 1991.
- Mixed-layer CAPE
- 1201 J/kg
- Mixed-layer CIN
- -8 J/kg
- Surface CAPE
- 1466 J/kg
- Mixed-layer LCL
- 971 m above ground
- 0-6 km bulk shear
- 91 kt
- 0-1 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 378 m²/s²
- 0-3 km storm-relative helicity
- 434 m²/s²
- Significant tornado parameter
- 3.4
- Supercell composite
- 12.5
- 0-3 km lapse rate
- 6.8 K/km
The surface observations
Battle Creek (BTL), 30 km from the path, in the two hours either side.
| Time (UTC) | Temp (°F) | Dew point (°F) | Wind | Gust (kt) | Pressure (mb) | Weather |
|---|---|---|---|---|---|---|
| 22:00 UTC | 71 | 59 | 200° 22 kt | 33 | 987.1 | |
| 23:00 UTC | 71 | 60 | 200° 20 kt | 28 | 985.4 | |
| 00:00 UTC | 70 | 58 | 200° 20 kt | 30 | 984.1 | |
| 00:24 UTC | 200° 15 kt | 25 | 982.7 | |||
| 00:37 UTC | 270° 30 kt | 55 | 984.8 | |||
| 01:00 UTC | 56 | 52 | 250° 15 kt | 25 | 984.4 | -TSRA |
| 01:22 UTC | 230° 15 kt | 985.1 |
From the Iowa Environmental Mesonet's archive of airport observations.
This ground now
The live radar over the trackEvery 1991 tornado in MichiganEvery tornado in Michigan since 1950Warnings in force in Michigan nowThe forecast where you are
The other tornadoes of March 27, 1991
28 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| March 27 | 12:30 AM CST | F1 | Chase, KS | 11.0 | 50 | $5,000 to $50,000 | ||
| March 27 | 10:35 PM PST | F1 | Orange, CA | 3.0 | 53 | |||
| March 27 | 2:00 AM PST | F1 | San Diego, CA | 0.2 | 10 | |||
| March 27 | 12:18 PM CST | F2 | Jackson, IA | 1.5 | 100 | 1 | $50,000 to $500,000 | |
| March 27 | 1:20 PM CST | F1 | Shelby, TN | 0.5 | 50 | $50 to $500 | ||
| March 27 | 1:50 PM CST | F2 | Green, WI | 32.0 | 440 | 1 | 5 | $500,000 to $5 million |
| March 27 | 3:50 PM CST | F0 | Will, IL | 3.0 | 50 | |||
| March 27 | 3:55 PM CST | F3 | Will, IL | 15.0 | 200 | 7 | $5 million to $50 million | |
| March 27 | 5:02 PM EST | F1 | Mecosta, MI | 1.0 | 20 | $500 to $5,000 | ||
| March 27 | 5:02 PM EST | F0 | Newaygo, MI | 0.5 | 10 | |||
| March 27 | 4:10 PM CST | F1 | Kankakee, IL | 0.5 | 50 | |||
| March 27 | 5:15 PM EST | F2 | Osceola, MI | 4.0 | 70 | $500 to $5,000 | ||
| March 27 | 5:30 PM EST | F1 | Osceola, MI | 2.0 | 40 | $50 to $500 | ||
| March 27 | 4:37 PM CST | F0 | Will, IL | 0.5 | 50 | $500 to $5,000 | ||
| March 27 | 6:05 PM EST | F0 | Osceola, MI | 1.0 | 10 | $50 to $500 | ||
| March 27 | 6:10 PM EST | F0 | Tippecanoe, IN | 0.2 | 10 | |||
| March 27 | 6:15 PM EST | F2 | Ogemaw, MI | 6.0 | 100 | $50,000 to $500,000 | ||
| March 27 | 6:15 PM EST | F3 | Ogemaw, MI | 35.0 | 100 | $500,000 to $5 million | ||
| March 27 | 6:20 PM EST | F3 | Ogemaw, MI | 21.0 | 100 | $500,000 to $5 million | ||
| March 27 | 6:25 PM EST | F0 | Cass, IN | 0.2 | 10 | |||
| March 27 | 7:00 PM EST | F2 | Ingham, MI | 5.0 | 60 | $50,000 to $500,000 | ||
| March 27 | 7:20 PM EST | F0 | Madison, IN | 0.1 | 20 | $500 to $5,000 | ||
| March 27 | 7:28 PM EST | F0 | Ingham, MI | 3.0 | 30 | |||
| March 27 | 7:37 PM EST | F3 | Hillsdale, MI | 5.0 | 400 | $5 million to $50 million | ||
| March 27 | 7:20 PM CST | F3 | Steuben, IN to OH | 21.0 | 200 | 1 | 24 | $5 million to $50 million |
| March 27 | 8:39 PM EST | F0 | Monroe, MI | 0.5 | 10 | |||
| March 27 | 8:45 PM EST | F0 | Monroe, MI | 0.5 | 10 | |||
| March 27 | 8:53 PM EST | F1 | Saint Clair, MI | 10.0 | 150 | $5,000 to $50,000 |
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.