Tornadoes · United States · Wisconsin · 2020
EF1 tornado, Starlake to Eagle River, Wisconsin, August 9, 2020
From Starlake to Eagle River, this EF1 tornado ran 6.2 miles across Vilas County on August 9, 2020, touching down at 7:44 PM CDT and reaching 400 yards wide. It killed nobody.
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 mph
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
EF186 to 110 mphthis tornado
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
- EF1
- Date
- August 9, 2020
- Touchdown
- 7:44 PM CDT (00:44 UTC)
- Lifted
- 7:58 PM CDT (00:58 UTC)
- On the ground
- 14 minutes
- Path length
- 6.2 miles (9.9 km)
- Path width
- 400 yards (366 m)
- Deaths
- 0
- Injuries
- 0
- County
- Vilas County
- Touchdown point
- 46.027, -89.472
- Lift-off point
- 46.051, -89.348
- Record number
- 2008091844-01
The damage survey
10 damage points were recorded along this path by NWS GRB, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 104 mph.
- Based on areial photos from WI DNR survey.
- Mixed hardwood and softwood trees uprooted and snapped.
- DNR Aerial Survey. Photo take just east of Star Lake Camp Ground looking NE along the damage path.
Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.
What the Weather Service recorded
An upper-level shortwave produced thunderstorms across north-central Wisconsin during the evening hours. Three tornadoes and wind damage was reported as these thunderstorms tracked through the area.
A tornado produced a path of tree damage (DI 27,28, DOD 3,4) from the eastern shore of Star Lake to the Upper Bucktabon Springs State Natural Area. Peak winds were estimated around 95 mph.
A tornado produced tree damage (DI 27,28, DOD 3,4) from east of St. Germain to southwest of Eagle River with intermittent touchdowns along the Wisconsin River. Peak winds were estimated around 90 mph.
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 |
|---|---|---|---|
| 00:26 UTC | 01:15 UTC | Severe Thunderstorm Warning | GRB |
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, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 19:55 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 surface observations
Eagle River (EGV), 16 km from the path, in the two hours either side.
| Time (UTC) | Temp (°F) | Dew point (°F) | Wind | Gust (kt) | Pressure (mb) | Weather |
|---|---|---|---|---|---|---|
| 22:55 UTC | 82 | 67 | 170° 7 kt | 15 | 1010.5 | |
| 23:15 UTC | 80.6 | 66.6 | 170° 11 kt | 19 | 1010.2 | |
| 23:35 UTC | 80 | 66.2 | 170° 10 kt | 19 | 1010.2 | |
| 23:55 UTC | 79.3 | 66.2 | 190° 7 kt | 1010.2 | ||
| 00:15 UTC | 78.3 | 65.5 | 180° 9 kt | 19 | 1010.2 | |
| 00:35 UTC | 77.2 | 65.5 | 180° 9 kt | 20 | 1009.8 | |
| 00:55 UTC | 76.5 | 65.8 | 180° 7 kt | 17 | 1009.8 | |
| 01:15 UTC | 76 | 66.2 | 190° 10 kt | 20 | 1009.5 | |
| 01:35 UTC | 76 | 66.6 | 260° 15 kt | 22 | 1009.8 | RA |
| 01:55 UTC | 69.4 | 69 | 300° 18 kt | 29 | 1011.9 | +RA |
| 02:15 UTC | 69.8 | 69 | 290° 10 kt | 20 | 1012.2 | |
| 02:35 UTC | 69.3 | 68.5 | 310° 11 kt | 1012.2 |
From the Iowa Environmental Mesonet's archive of airport observations.
The radar
The Marquette radar (KMQT), 153 km away, was scanning. The volume nearest the touchdown began at 00:43 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 |
|---|---|---|---|---|
| 00:41 UTC | TSTM WND DMG | 1 Wnw Star Lake | Vilas, WI | NUMEROUS TREES DOWN AROUND THE AREA, IMPACTING MULTIPLE CAMP SITES. NUMEROUS ROADS COMPLETELY BLOCKED BY FALLEN TREES. NO INJURIES REPORTED AT THE TIME OF THE REPORT. TIME ESTIMATED VIA RADAR. |
| 00:44 UTC | TORNADO | 1 Wsw Star Lake | Vilas, WI | EYE WITNESS RECORDED TORNADO SKIPPING OFF THE LAKE BEFORE SETTING DOWN OFFSHORE OF EAST STAR LAKE CAMPGROUND. THE TORNADO DOWNED NUMEROUS TREES AND POWER LINES ON ITS WAY ACROSS THE CAMPSITE AND CONTINUED FOR 6 MILES NOR |
| 01:10 UTC | TSTM WND DMG | 2 Se Land O Lakes | Vilas, WI | NUMEROUS TREES DOWN. SOME TREES SHEARED OFF. |
From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.
This ground now
The live radar over the trackEvery 2020 tornado in WisconsinEvery tornado in Wisconsin since 1950Warnings in force in Wisconsin nowThe forecast where you are
The other tornadoes of August 9, 2020
12 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| August 9 | 11:58 AM CDT | EF0 | Cavalier, ND | 0.3 | 40 | |||
| August 9 | 2:02 PM CDT | EF1 | LaMoure, ND | 0.9 | 100 | $225,000 | ||
| August 9 | 2:13 PM CDT | Unrated | LaMoure, ND | 2.2 | 100 | |||
| August 9 | 2:13 PM CDT | EF1 | Pennington, MN | 22.0 | 200 | |||
| August 9 | 2:17 PM CDT | EF1 | Barnes, ND | 2.9 | 150 | |||
| August 9 | 2:19 PM CDT | Unrated | LaMoure, ND | 0.3 | 50 | |||
| August 9 | 2:40 PM CDT | EF0 | Traill, ND | 2.0 | 40 | |||
| August 9 | 3:20 PM CDT | EF1 | Beltrami, MN | 0.3 | 100 | |||
| August 9 | 6:15 PM EDT | EF0 | Manatee, FL | 0.2 | 100 | $20,000 | ||
| August 9 | 8:28 PM CDT | EF1 | Vilas, WI | 5.9 | 250 | |||
| August 9 | 9:12 PM CDT | EF1 | Iron, WI to MI | 4.6 | 250 | $70,000 | ||
| August 9 | 9:56 PM CDT | EF1 | Iron, MI | 3.8 | 250 | $100,000 |
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.