Tornadoes · United States · Massachusetts · 1968

F1 tornado, Worcester County, Massachusetts, July 17, 1968

This F1 tornado ran 0.3 miles across Worcester County on July 17, 1968, touching down at 6:30 PM GMT-4 and reaching 17 yards wide. It killed nobody, and did $500 to $5,000 of property damage.

The rating scale

Tracks are drawn in the color of the rating. The Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. F040 to 72 mph

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

  2. F173 to 112 mphthis tornado

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

  3. F2113 to 157 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. F3158 to 206 mph

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. F4207 to 260 mph

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

  6. F5261 to 318 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
F1
Date
July 17, 1968
Touchdown
6:30 PM GMT-4 (22:30 UTC)
Path length
0.3 miles (0.5 km)
Path width
17 yards (16 m)
Deaths
0
Injuries
0
Property damage
$500 to $5,000
County
Worcester County
Touchdown point
42.080, -72.100
Record number
449

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 (KALB), 12:00Z

10.5 hours before the tornado, 157 km from the path. July 17, 1968.

Skew-T log-pSkew-T log-p diagram, Albany, NY at 12:00Z on 1968-07-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 401 joules per kilogram, CIN -125, lifted condensation level 967 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°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 1968-07-17The 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 0 square meters per square second, 0 to 6 km bulk shear 9 knots.1939Sfc1 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
401 J/kg
Mixed-layer CIN
-125 J/kg
Surface CAPE
973 J/kg
Mixed-layer LCL
967 m above ground
0-6 km bulk shear
9 kt
0-1 km bulk shear
10 kt
0-1 km storm-relative helicity
0 m²/s²
0-3 km storm-relative helicity
18 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.0 K/km

Open this sounding in Storm Lab

Albany, NY (KALB), 00:00Z

1.5 hours after it, 157 km from the path. July 18, 1968.

Skew-T log-pSkew-T log-p diagram, Albany, NY at 00:00Z on 1968-07-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1050 joules per kilogram, CIN -72, lifted condensation level 1017 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°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 1968-07-18The 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 -10 square meters per square second, 0 to 6 km bulk shear 16 knots.1939Sfc1 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
1050 J/kg
Mixed-layer CIN
-72 J/kg
Surface CAPE
1879 J/kg
Mixed-layer LCL
1017 m above ground
0-6 km bulk shear
16 kt
0-1 km bulk shear
12 kt
0-1 km storm-relative helicity
-10 m²/s²
0-3 km storm-relative helicity
-4 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.1
0-3 km lapse rate
5.5 K/km

Open this sounding in Storm Lab

The surface observations

Worcester (ORH), 28 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
21:00 UTC8068220° 13 kt1016.9TSRA DZ
00:00 UTC7064210° 5 kt1018.6DZ

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

This ground now

The live radar over the trackEvery 1968 tornado in MassachusettsEvery tornado in Massachusetts since 1950Warnings in force in Massachusetts nowThe forecast where you are

The other tornadoes of July 17, 1968

10 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
July 171:47 PM GMT-5F0Stearns, MN0.110
July 173:55 PM GMT-4F2Hillsborough, NH0.117$5,000 to $50,000
July 176:30 PM GMT-5F0Carson, TX0.5100
July 176:55 PM GMT-5F0Callaway, MO0.550$500 to $5,000
July 177:15 PM GMT-5F1Comanche, KS0.5300
July 177:15 PM GMT-5F1Comanche, KS0.110
July 177:30 PM GMT-5F1Warren, IL3.8127$50 to $500
July 179:02 PM GMT-5F0Carson, TX4.533
July 179:02 PM GMT-5F0Gray, TX3.833
July 179:35 PM GMT-5F0Wheeler, TX0.110

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.