Tornadoes · United States · Michigan · 2011
EF0 tornado, Ontonagon, Michigan, August 19, 2011
This EF0 tornado ran 1.5 miles across Ontonagon County on August 19, 2011, touching down at 8:05 AM EDT and reaching 125 yards wide. It killed nobody, and did $20,000 of property damage.
The rating scale
Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.
EF065 to 85 mphthis tornado
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
EF186 to 110 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
EF2111 to 135 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.
EF3136 to 165 mph
Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.
EF4166 to 200 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
EF5over 200 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
- EF0
- Date
- August 19, 2011
- Touchdown
- 8:05 AM EDT (12:05 UTC)
- Lifted
- 8:09 AM EDT (12:09 UTC)
- On the ground
- 4 minutes
- Path length
- 1.5 miles (2.5 km)
- Path width
- 125 yards (114 m)
- Deaths
- 0
- Injuries
- 0
- Property damage
- $20,000
- County
- Ontonagon County
- Touchdown point
- 46.865, -89.318
- Lift-off point
- 46.872, -89.287
- Record number
- 1108190605-01
What the Weather Service recorded
A deep low pressure system moving through northwest Ontario pushed a warm front across western Upper Michigan in the morning hours...followed by a cold frontal passage in the afternoon. The frontal boundaries produced several severe thunderstorms and two weak tornadoes over western Upper Michigan on the 19th.
A strong EF0 tornado with winds estimated around 85 mph touched down at the River Pines RV Park and Campground and then skipped northeastward across the village lifting on the east side of the Ontonagon Golf Course. Most of the damage was confined to snapped and uprooted trees, snapped power poles, a small flipped boat, minor roof damage, and some structural damage to a garage. There were no injuries.
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) | Expired | Product | Office |
|---|---|---|---|
| 11:45 UTC | 12:45 UTC | Severe Thunderstorm Warning | MQT |
| 12:21 UTC | 13:00 UTC | Severe Thunderstorm Warning | MQT |
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 General Thunderstorms Risk. The outlook in force was issued at 05:26 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.
Green Bay/Straub, WI (KGRB), 12:00Z
0.1 hours before the tornado, 282 km from the path. August 19, 2011.
- Mixed-layer CAPE
- 123 J/kg
- Mixed-layer CIN
- -204 J/kg
- Surface CAPE
- 0 J/kg
- Mixed-layer LCL
- 1324 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km bulk shear
- 9 kt
- 0-1 km storm-relative helicity
- 15 m²/s²
- 0-3 km storm-relative helicity
- 65 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
- 0-3 km lapse rate
- 3.9 K/km
Green Bay/Straub, WI (KGRB), 00:00Z
11.9 hours after it, 282 km from the path. August 20, 2011.
- Mixed-layer CAPE
- 1246 J/kg
- Mixed-layer CIN
- -81 J/kg
- Surface CAPE
- 2243 J/kg
- Mixed-layer LCL
- 1558 m above ground
- 0-6 km bulk shear
- 46 kt
- 0-1 km bulk shear
- 17 kt
- 0-1 km storm-relative helicity
- 122 m²/s²
- 0-3 km storm-relative helicity
- 162 m²/s²
- Significant tornado parameter
- 0.4
- Supercell composite
- 7.7
- 0-3 km lapse rate
- 7.6 K/km
The radar
The Marquette radar (KMQT), 139 km away, was scanning. The volume nearest the touchdown began at 12:05 UTC.
Open the radar archive at this moment, over the track
Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.
What was reported nearby
Local storm reports within 60 km of the path, in the three hours either side.
| Time (UTC) | Report | Where | County | Remark |
|---|---|---|---|---|
| 12:05 UTC | TSTM WND DMG | Ontonagon | Ontonagon, MI | VARIOUS TREES DOWN ALONG US45 AND M38.SOME FELL ON POWERLINES. |
| 12:05 UTC | HAIL 0.25 | 8 Wsw Ontonagon | Ontonagon, MI | ESTIMATED WIND GUSTS BETWEEN 40-50 MPH ALSO. POWER IS OUT AND MEASURED 0.75 INCHES OF RAIN IN 20 MINUTES. SMALL BRANCHES 1-2 INCH DIAMETER DOWN. |
| 12:05 UTC | TORNADO | Ontonagon | Ontonagon, MI | SEVERAL TREES UPROOTED AND POWER POLES SNAPPED. CAMPER BLOWN ACROSS ROAD. TORNADO WITNESSED BY DPW WORKERS. |
| 12:15 UTC | TSTM WND DMG | 4 S Mass City | Ontonagon, MI | APPLE TREE 6 INCHES IN DIAMETER DOWN. VARIOUS BRANCHES 3 INCHES IN DIAMETER DOWN. HANGING PLANTS BLOWN OFF THE PORCH. WIND ESTIMATED AT 45-50 MPH. |
From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.
This ground now
The live radar over the trackEvery 2011 tornado in MichiganEvery tornado in Michigan since 1950Warnings in force in Michigan nowThe forecast where you are
The other tornadoes of August 19, 2011
1 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| August 19 | 4:45 PM CDT | EF1 | Marinette, WI to MI | 7.9 | 250 | 1 | $125,000 |
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.