Tornadoes · United States · Arizona · 1984

F1 tornado, Pima County, Arizona, July 16, 1984

This F1 tornado ran 0.1 miles across Pima County on July 16, 1984, touching down at 7:50 PM MST and reaching 20 yards wide. It killed nobody, and did $5,000 to $50,000 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 16, 1984
Touchdown
7:50 PM MST (02:50 UTC)
Path length
0.1 miles (0.2 km)
Path width
20 yards (18 m)
Deaths
0
Injuries
0
Property damage
$5,000 to $50,000
County
Pima County
Touchdown point
32.170, -110.880
Record number
747

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.

Tuscon, AZ (KTUS), 00:00Z

2.8 hours before the tornado, 2 km from the path. July 17, 1984.

Skew-T log-pSkew-T log-p diagram, Tuscon, AZ at 00:00Z on 1984-07-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 890 joules per kilogram, CIN -117, lifted condensation level 2019 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, Tuscon, AZ at 00:00Z on 1984-07-17The 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 -27 square meters per square second, 0 to 6 km bulk shear 24 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
890 J/kg
Mixed-layer CIN
-117 J/kg
Surface CAPE
1376 J/kg
Mixed-layer LCL
2019 m above ground
0-6 km bulk shear
24 kt
0-1 km bulk shear
5 kt
0-1 km storm-relative helicity
-27 m²/s²
0-3 km storm-relative helicity
33 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.4
0-3 km lapse rate
8.2 K/km

Open this sounding in Storm Lab

Tuscon, AZ (KTUS), 12:00Z

9.2 hours after it, 2 km from the path. July 17, 1984.

Skew-T log-pSkew-T log-p diagram, Tuscon, AZ at 12:00Z on 1984-07-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 175 joules per kilogram, CIN -274, lifted condensation level 1072 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, Tuscon, AZ at 12:00Z on 1984-07-17The 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 17 square meters per square second, 0 to 6 km bulk shear 15 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
175 J/kg
Mixed-layer CIN
-274 J/kg
Surface CAPE
255 J/kg
Mixed-layer LCL
1072 m above ground
0-6 km bulk shear
15 kt
0-1 km bulk shear
16 kt
0-1 km storm-relative helicity
17 m²/s²
0-3 km storm-relative helicity
122 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.6 K/km

Open this sounding in Storm Lab

The surface observations

Davis-Monthan Afb (DMA), 1 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
01:00 UTC9362310° 13 kt1013.5
01:05 UTC320° 10 kt+TSRA
02:00 UTC9161310° 9 kt1013.9TS
03:00 UTC686430° 33 kt401017.6TSRA
03:40 UTC60° 10 kt1017.9+TSRA
04:00 UTC736460° 8 kt1017.6TSRA

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

This ground now

The live radar over the trackEvery 1984 tornado in ArizonaEvery tornado in Arizona since 1950Warnings in force in Arizona nowThe forecast where you are

The other tornadoes of July 16, 1984

8 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
July 164:00 PM CDTF1Hennepin, MN4.5150$500,000 to $5 million
July 165:15 PM CDTF1Steele, MN1.0100$5,000 to $50,000
July 164:43 PM MDTF0Keith, NE0.117
July 165:44 PM CDTF0Dickinson, IA0.110
July 165:45 PM CDTF1Jackson, MN2.5200$50,000 to $500,000
July 166:03 PM CDTF0Emmet, IA0.110
July 167:40 PM MDTF1Elbert, CO1.050
July 168:10 PM MSTF1Pima, AZ0.120

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.