Tornadoes · United States · Texas · 2006

F1 tornado, Hye to Johnson City, Texas, April 20, 2006

From Hye to Johnson City, this F1 tornado ran 0.7 miles across Blanco County on April 20, 2006, touching down at 3:58 PM CDT and reaching 50 yards wide. It killed nobody, and did $150,000 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
April 20, 2006
Touchdown
3:58 PM CDT (20:58 UTC)
Path length
0.7 miles (1.1 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
Property damage
$150,000
County
Blanco County
Touchdown point
30.280, -98.500
Lift-off point
30.280, -98.480
Record number
407

What the Weather Service recorded

A small tornado was spotted by the public as it touched down east of Hye. The tornado destroyed a barn, then lifted back up into the parent thunderstorm. No other damage was indicated.

A second tornado touched down west of Johnson City very close to the time of the first tornado. This tornado was on the ground for three-quarters of a mile and destroyed 3 barns as it moved east.

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

The warnings

18 minutes of warning. NWS EWX issued a tornado warning for this county at 20:40 UTC, 18 minutes before the tornado touched down, in force until 21:15 UTC.

The county was under a tornado watch, issued at 20:25 UTC and running to 03:00 UTC.

Issued (UTC)ExpiredProductOffice
16:18 UTC20:24 UTCSevere Thunderstorm WatchEWX
19:16 UTC20:15 UTCSevere Thunderstorm WarningEWX
20:21 UTC21:15 UTCSevere Thunderstorm WarningEWX
20:25 UTC03:00 UTCTornado WatchEWX
20:40 UTC21:15 UTCTornado WarningEWX
21:11 UTC21:45 UTCSevere Thunderstorm WarningEWX

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 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 19:46 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.

Del Rio, TX (KDRT), 12:00Z

9.0 hours before the tornado, 248 km from the path. April 20, 2006.

Skew-T log-pSkew-T log-p diagram, Del Rio, TX at 12:00Z on 2006-04-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1378 joules per kilogram, CIN -155, lifted condensation level 702 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, Del Rio, TX at 12:00Z on 2006-04-20The 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 82 square meters per square second, 0 to 6 km bulk shear 39 knots.19395878Sfc1 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
1378 J/kg
Mixed-layer CIN
-155 J/kg
Surface CAPE
556 J/kg
Mixed-layer LCL
702 m above ground
0-6 km bulk shear
39 kt
0-1 km bulk shear
24 kt
0-1 km storm-relative helicity
82 m²/s²
0-3 km storm-relative helicity
143 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.8
0-3 km lapse rate
4.0 K/km

Open this sounding in Storm Lab

Del Rio, TX (KDRT), 00:00Z

3.0 hours after it, 248 km from the path. April 21, 2006.

Skew-T log-pSkew-T log-p diagram, Del Rio, TX at 00:00Z on 2006-04-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 2847 joules per kilogram, CIN -11, lifted condensation level 913 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, Del Rio, TX at 00:00Z on 2006-04-21The 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 68 square meters per square second, 0 to 6 km bulk shear 53 knots.19395878Sfc1 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
2847 J/kg
Mixed-layer CIN
-11 J/kg
Surface CAPE
3463 J/kg
Mixed-layer LCL
913 m above ground
0-6 km bulk shear
53 kt
0-1 km bulk shear
7 kt
0-1 km storm-relative helicity
68 m²/s²
0-3 km storm-relative helicity
81 m²/s²
Significant tornado parameter
1.0
Supercell composite
4.0
0-3 km lapse rate
6.1 K/km

Open this sounding in Storm Lab

The surface observations

Fredericksburg/Gillespie County (T82), 40 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
19:05 UTC6862.690° 12 kt1011.5
19:25 UTC66.262.690° 8 kt1011.2
20:05 UTC64.460.840° 11 kt341011.2
20:25 UTC62.660.80° 0 kt1011.9
20:45 UTC64.462.670° 5 kt1011.5
21:05 UTC64.462.690° 8 kt1011.2
21:25 UTC66.262.690° 6 kt1011.2
21:45 UTC6864.4100° 7 kt1010.8
22:05 UTC6864.4100° 8 kt1010.8
22:25 UTC6864.4110° 5 kt1010.8
22:45 UTC6864.480° 4 kt1010.8

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

The radar

The Austin/San Antonio radar (KEWX), 78 km away, was scanning. The volume nearest the touchdown began at 20:59 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
19:55 UTCHAIL 0.5FredericksburgGillespie, TXPEA TO MARBLE HAIL COVERING THE GROUND.
20:20 UTCHAIL 0.7510 W AustinTravis, TXDIME TO PENNY SIZE HAIL.
20:20 UTCHAIL 0.7510 W AustinTravis, TXDIME TO PENNY SIZE HAIL IN WESTERN AUSTIN.
20:30 UTCHAIL 0.512 Nw AustinTravis, TXHALF INCH AND LARGER HAIL AT WESTWOOD HIGH SCHOOL.
20:50 UTCHAIL 1.75Johnson CityBlanco, TXGOLFBALL AT THE LBJ PARK HEADQUARTERS.
21:01 UTCHAIL 13 N Johnson CityBlanco, TX
21:46 UTCHAIL 0.7515 E FredericksburgGillespie, TX
21:46 UTCHAIL 1FredericksburgGillespie, TX
21:48 UTCHAIL 15 Ne Bee CaveTravis, TX2300 BLOCK OF MECCA DRIVE.
21:48 UTCHAIL 310 W AustinTravis, TXTHREE INCH HAIL REPORTED NEAR HUDSON BEND IN WESTERN AUSTIN.
21:58 UTCHAIL 0.7511 Nw AustinTravis, TXPENNY SIZE HAIL AT ANDERSON MILL.
22:15 UTCFUNNEL CLOUDJohnson CityBlanco, TXFUNNEL CLOUD REPORTED BY PARK OFFICALS.
22:15 UTCFUNNEL CLOUDJohnson CityBlanco, TXFUNNEL CLOUD REPORTED BY PARK OFFICIALS.
22:15 UTCHAIL 1Johnson CityBlanco, TX

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

This ground now

The live radar over the trackEvery 2006 tornado in TexasEvery tornado in Texas since 1950Warnings in force in Texas nowThe forecast where you are

The other tornadoes of April 20, 2006

1 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
April 203:55 PM CDTF1Blanco, TX0.330$50,000

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.