EF1 tornado, Westfield to Powers Corner, Maine, May 31, 2009

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.

Rating

EF1

Date

May 31, 2009

Touchdown

5:42 PM EDT (21:42 UTC)

Lifted

5:57 PM EDT (21:57 UTC)

On the ground

15 minutes

Path length

7.0 miles (11.3 km)

Path width

100 yards (91 m)

Deaths

0

Injuries

0

County

Aroostook County

Touchdown point

46.600, -67.930

Lift-off point

46.660, -67.810

Record number

0905311542-01

Severe thunderstorms developed across northern Maine during the late afternoon and evening of the 31st in advance of a cold front and upper disturbance crossing the region. The thunderstorms produced damaging winds...large hail and several tornados.

A mini-supercell thunderstorm produced an EF1 tornado near the town of Westfield. The tornado began near the Little Burnt Land Stream area...then was intermittently on the ground before lifting just west of U.S. Route 1 near Westfield. Along the tornado path...hundreds of trees were snapped and uprooted in intermittent swaths and patches (DI 27, DOD 4). Several outbuildings were also damaged or destroyed along Simpson and Shorey Roads near Westfield. Based on the damage...the tornado winds were estimated at around 95 mph. This same thunderstorm continued tracking northeast across U.S. Route 1 and Westfield...producing another tornado several miles further along its track in the vicinity of Easton.

A mini-supercell thunderstorm produced an EF1 tornado in the vicinity of Easton. The tornado touched down near the Egypt Road and was intermittently on the ground while tracking northeast across U.S. Route 1A south of Easton before dissipating just before crossing the border into New Brunswick. Along the tornado path...hundreds of trees were snapped or uprooted in intermittent swaths and patches (DI 27, DOD 4). Several outbuildings were also damaged or destroyed. The metal roof of a dairy barn was destroyed in Easton. Based on the damage...the tornado winds were estimated at around 95 mph. The average path width was around 50 yards. This same thunderstorm had produced another tornado several minutes earlier in the vicinity of Westfield.

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

17 minutes of warning. NWS CAR issued a tornado warning for this county at 21:25 UTC, 17 minutes before the tornado touched down, in force until 22:00 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 Slight Risk. The outlook in force was issued at 20:16 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.

The Caribou radar (KCBW), 66 km away, was scanning. The volume nearest the touchdown began at 21:42 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 MaineEvery tornado in Maine since 1950Warnings in force in Maine nowThe forecast where you are

2 more were confirmed in the United States that day.

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.