Tornadoes · United States · Michigan · 1993

F1 tornado, Grayling, Michigan, August 30, 1993

This F1 tornado ran 8.0 miles across Crawford County on August 30, 1993, touching down at 4:35 PM EDT and reaching 50 yards wide. It killed nobody, and did $5,000 to $50,000 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.

  1. F040 to 72 mph

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

  2. F173 to 112 mphthis tornado

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

  3. 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.

  4. F3158 to 206 mph

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

  5. F4207 to 260 mph

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

  6. 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.

  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.

The record

Rating
F1
Date
August 30, 1993
Touchdown
4:35 PM EDT (20:35 UTC)
Path length
8.0 miles (12.9 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
Property damage
$5,000 to $50,000
County
Crawford County
Touchdown point
44.520, -84.700
Lift-off point
44.570, -84.550
Record number
1025

What the Weather Service recorded

A small tornado touched down 2 miles north of the Crawford-Roscommon County border and 1.5 miles west of Interstate 75 then moved northeast for just under 8 miles before lifting. It dropped a tree on a house at the initial touchdown location then moved northeast generally tree-topping and doing only minor damage until it crossed Interstate 75. After crossing Interstate 75 the tornado strengthened and began doing widespread tree damage. In the next 1.5 miles it destroyed nearly a thousand large hardwoods and pines damaged a travel trailer and outbuildings at one residence and damaged the roof of another then tore the roof off of a 12- X 60-foot mobile home. After passing the intersection of Johnson and Seven Mile Roads 5.5 miles northwest of the village of Roscommon it proceeded northeast through a heavily wooded area for nearly another 4 miles uprooting or snapping off well in excess of another thousand trees.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

The warnings

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.

Issued (UTC)ExpiredProductOffice
22:05 UTC22:30 UTCSevere Thunderstorm WarningDTX
01:46 UTC02:30 UTCSevere Thunderstorm WarningDTX

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 Slight Risk. The outlook in force was issued at 06:13 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.

Sault Ste Marie, MI (KY62), 12:00Z

8.6 hours before the tornado, 216 km from the path. August 30, 1993.

Skew-T log-pSkew-T log-p diagram, Sault Ste Marie, MI at 12:00Z on 1993-08-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 14 joules per kilogram, CIN -4, lifted condensation level 535 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Sault Ste Marie, MI at 12:00Z on 1993-08-30The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 72 square meters per square second, 0 to 6 km bulk shear 28 knots.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
14 J/kg
Mixed-layer CIN
-4 J/kg
Surface CAPE
6 J/kg
Mixed-layer LCL
535 m above ground
0-6 km bulk shear
28 kt
0-1 km bulk shear
17 kt
0-1 km storm-relative helicity
72 m²/s²
0-3 km storm-relative helicity
115 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
3.4 K/km

Open this sounding in Storm Lab

Sault Ste Marie, MI (KY62), 00:00Z

3.4 hours after it, 216 km from the path. August 31, 1993.

Skew-T log-pSkew-T log-p diagram, Sault Ste Marie, MI at 00:00Z on 1993-08-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 250 joules per kilogram, CIN -13, lifted condensation level 544 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Sault Ste Marie, MI at 00:00Z on 1993-08-31The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 278 square meters per square second, 0 to 6 km bulk shear 64 knots.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
250 J/kg
Mixed-layer CIN
-13 J/kg
Surface CAPE
39 J/kg
Mixed-layer LCL
544 m above ground
0-6 km bulk shear
64 kt
0-1 km bulk shear
36 kt
0-1 km storm-relative helicity
278 m²/s²
0-3 km storm-relative helicity
339 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.3
0-3 km lapse rate
4.7 K/km

Open this sounding in Storm Lab

This ground now

The live radar over the trackEvery 1993 tornado in MichiganEvery tornado in Michigan since 1950Warnings in force in Michigan nowThe forecast where you are

The other tornadoes of August 30, 1993

1 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 308:20 AM EDTF0Franklin, FL0.110

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.