EF0 tornado, Williamstown to Washington, Vermont, July 16, 2009

1. EF065 to 85 mphthis tornado

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

2. EF186 to 110 mph

   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.

Rating

EF0

Date

July 16, 2009

Touchdown

7:05 PM EDT (23:05 UTC)

Lifted

7:09 PM EDT (23:09 UTC)

On the ground

4 minutes

Path length

2.7 miles (4.4 km)

Path width

425 yards (389 m)

Deaths

0

Injuries

0

Property damage

$50,000

Crop damage

$25,000

County

Orange County

Touchdown point

44.071, -72.529

Lift-off point

44.051, -72.482

Record number

0907161705-01

On July 16th, a strong upper atmospheric area of low pressure was located north of the Great Lakes in south central Canada. In addition, a significant mid-level shortwave and associated surface low moved across the eastern Great Lakes, while a warm front and subsequent cold front swept across northern New York and Vermont during the afternoon and evening.||Numerous thunderstorms developed and moved across Vermont, in a moderate to strong unstable atmosphere during the afternoon and evening. In addition there were a few super-cell thunderstorms that produced very large hail, up to 3.3 inches in diameter in Westford (Chittenden county) with numerous reports of damage to vehicles, homes, crop and livestock and a brief EF-0 tornado along the Williamstown-Chelsea town line (Orange county). ||The measured 3.3 inch diameter hail in Westford, also had a circumference of 6.8 inches and has been determined by the State Climate Extremes Committee as the largest recorded hail stone in Vermont.

A tornado produced a broken path of damage. The most significant damage occurred to a blown barn roof near the beginning of the track along South Hill Road near Lighthouse Road In Williamstown. The tornado moved southeast and lifted near the|intersection of Stellar and Williamstown Roads in Chelsea.||The majority of the damage was downed softwood trees along the Chelsea/Williamstown Road. The north side of the path had over a hundred trees blown down in a east to west direction. Meanwhile on the south side of the path, dozens of trees were blown in a west to east direction.

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

12 minutes of warning. NWS BTV issued a tornado warning for this county at 22:53 UTC, 12 minutes before the tornado touched down, in force until 23:45 UTC.

The county was under a severe thunderstorm watch, issued at 20:56 UTC and running to 00:00 UTC.

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 Storm Prediction Center had this point in a General Thunderstorms Risk. The outlook in force was issued at 20:04 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 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.

Barre-Montpelier (MPV), 16 km from the path, in the two hours either side.

From the Iowa Environmental Mesonet's archive of airport observations.

The Burlington radar (KCXX), 73 km away, was scanning. The volume nearest the touchdown began at 23:04 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.

Local storm reports within 60 km of the path, in the three hours either side.

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

The live radar over the trackEvery 2009 tornado in VermontEvery tornado in Vermont since 1950Warnings in force in Vermont nowThe forecast where you are

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.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.