Tornadoes · United States · Vermont · 2019

EF1 tornado, Windham, Vermont, August 21, 2019

This EF1 tornado ran 0.8 miles across Windham County on August 21, 2019, touching down at 5:05 PM EDT and reaching 350 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.

  1. EF065 to 85 mph

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

  2. EF186 to 110 mphthis tornado

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

  3. 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.

  4. 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.

  5. EF4166 to 200 mph

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

  6. 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.

  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
EF1
Date
August 21, 2019
Touchdown
5:05 PM EDT (21:05 UTC)
Lifted
5:10 PM EDT (21:10 UTC)
On the ground
5 minutes
Path length
0.8 miles (1.2 km)
Path width
350 yards (320 m)
Deaths
0
Injuries
0
County
Windham County
Touchdown point
43.190, -72.730
Lift-off point
43.190, -72.720
Record number
1908211505-01

What the Weather Service recorded

A strong upper level shortwave moved into a humid and unstable airmass. This resulted in an areas of heavy rain and an EF1 tornado in Windham, Vermont.

The National Weather Service storm survey team confirmed a high-end EF1 tornado in Windham, VT. The team found a swath of almost continuous damage in a 3/4 mile by 350 yard area. There was shingle and siding damage to several homes. Many dozen of trees were violently snapped or uprooted. Outdoor furniture, shingles and siding were tossed hundreds of yards. Based on the degree of damage, the estimated wind speed of 105 to 110 mph was determined, which is a high-end EF1 tornado.

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.

The county was under a severe thunderstorm watch, issued at 17:53 UTC and running to 01:00 UTC.

Issued (UTC)ExpiredProductOffice
13:21 UTC15:15 UTCFlood AdvisoryALY
17:53 UTC01:00 UTCSevere Thunderstorm WatchALY

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 19:57 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.

Albany, NY (KALY), 12:00Z

9.1 hours before the tornado, 106 km from the path. August 21, 2019.

Skew-T log-pSkew-T log-p diagram, Albany, NY at 12:00Z on 2019-08-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 169 joules per kilogram, CIN -100, lifted condensation level 698 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, Albany, NY at 12:00Z on 2019-08-21The 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 168 square meters per square second, 0 to 6 km bulk shear 34 knots.193958Sfc1 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
169 J/kg
Mixed-layer CIN
-100 J/kg
Surface CAPE
118 J/kg
Mixed-layer LCL
698 m above ground
0-6 km bulk shear
34 kt
0-1 km bulk shear
19 kt
0-1 km storm-relative helicity
168 m²/s²
0-3 km storm-relative helicity
208 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3
0-3 km lapse rate
4.7 K/km

Open this sounding in Storm Lab

Albany, NY (KALY), 00:00Z

2.9 hours after it, 106 km from the path. August 22, 2019.

Skew-T log-pSkew-T log-p diagram, Albany, NY at 00:00Z on 2019-08-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 73 joules per kilogram, CIN -55, lifted condensation level 837 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, Albany, NY at 00:00Z on 2019-08-22The 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 62 square meters per square second, 0 to 6 km bulk shear 36 knots.193958Sfc1 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
73 J/kg
Mixed-layer CIN
-55 J/kg
Surface CAPE
533 J/kg
Mixed-layer LCL
837 m above ground
0-6 km bulk shear
36 kt
0-1 km bulk shear
24 kt
0-1 km storm-relative helicity
62 m²/s²
0-3 km storm-relative helicity
65 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5
0-3 km lapse rate
4.8 K/km

Open this sounding in Storm Lab

The radar

The Albany radar (KENX), 128 km away, was scanning. The volume nearest the touchdown began at 21:03 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)ReportWhereCountyRemark
21:05 UTCTORNADO1 N WindhamWindham, VTEF1 TORNADO CONFIRMED. ESTIMATED MAXIMUM WIND SPEED 105 TO 100 MPH.
21:05 UTCTORNADO1 N WindhamWindham, VTEF1 TORNADO CONFIRMED. ESTIMATED MAXIMUM WIND SPEED 105 TO 110 MPH.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2019 tornado in VermontEvery tornado in Vermont since 1950Warnings in force in Vermont nowThe forecast where you are

The other tornadoes of August 21, 2019

3 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 212:24 PM EDTEF0Fulton, NY0.5150
August 213:35 PM EDTEF1Saratoga, NY0.475
August 217:59 PM CDTEF0Macon, IL0.110

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.