Tornadoes · United States · California · 2006

F1 tornado, Modesto, California, April 14, 2006

This F1 tornado ran 0.5 miles across Stanislaus County on April 14, 2006, touching down at 4:35 PM PDT. It killed nobody, and did $10,000 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 14, 2006
Touchdown
4:35 PM PDT (23:35 UTC)
Path length
0.5 miles (0.8 km)
Path width
0 yards (0 m)
Deaths
0
Injuries
0
Property damage
$10,000
County
Stanislaus County
Touchdown point
37.650, -121.000
Lift-off point
37.650, -121.000
Record number
370

What the Weather Service recorded

Members of the general public reported seeing a tornado near the intersection of Millbrook Ave and Floyd Ave in Modesto.A tornado moved through Modesto from near the intersection of Millbrook Ave and Floyd Ave to near the intersection of Lauding Way and Beck Way. The primary damage was to roofing tiles on several buildings and to area fencing.

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

The warnings

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.

Issued (UTC)ExpiredProductOffice
22:37 UTC23:15 UTCSevere Thunderstorm WarningSTO
22:37 UTC23:15 UTCSevere Thunderstorm WarningSTO

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 General Thunderstorms Risk. The outlook in force was issued at 22:14 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.

Oakland, CA (KOAK), 12:00Z

11.6 hours before the tornado, 106 km from the path. April 14, 2006.

Skew-T log-pSkew-T log-p diagram, Oakland, CA at 12:00Z on 2006-04-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -69772, lifted condensation level 1163 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 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, Oakland, CA at 12:00Z on 2006-04-14The 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 -36 square meters per square second, 0 to 6 km bulk shear 13 knots.193958Sfc1 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
0 J/kg
Mixed-layer CIN
-69772 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1163 m above ground
0-6 km bulk shear
13 kt
0-1 km bulk shear
3 kt
0-1 km storm-relative helicity
-36 m²/s²
0-3 km storm-relative helicity
83 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.7 K/km

Open this sounding in Storm Lab

Oakland, CA (KOAK), 00:00Z

0.4 hours after it, 106 km from the path. April 15, 2006.

Skew-T log-pSkew-T log-p diagram, Oakland, CA at 00:00Z on 2006-04-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -75771, lifted condensation level 865 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 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, Oakland, CA at 00:00Z on 2006-04-15The 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 19 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
0 J/kg
Mixed-layer CIN
-75771 J/kg
Surface CAPE
4 J/kg
Mixed-layer LCL
865 m above ground
0-6 km bulk shear
16 kt
0-1 km bulk shear
11 kt
0-1 km storm-relative helicity
19 m²/s²
0-3 km storm-relative helicity
6 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.9 K/km

Open this sounding in Storm Lab

The surface observations

Modesto City/Sham (MOD), 5 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
21:53 UTC7453 5 kt1004.7
22:14 UTC6853.6170° 6 kt1004.7RA
22:18 UTC6853.6 4 kt1004.7-RA
22:53 UTC6755360° 9 kt1005.1
23:53 UTC6856320° 3 kt1005.4
00:53 UTC6555260° 3 kt1006.1-RA

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

The radar

The San Francisco radar (KMUX), 97 km away, was scanning. The volume nearest the touchdown began at 23:37 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
22:45 UTCFLOODRiverbankStanislaus, CA15 TO 20 HOMES HAVE SOME FLOODING IN THEM. 5 TO 6 BUSINESS HAVE MINOR FLOODING.
22:45 UTCTORNADOModestoStanislaus, CAEYEWITNESSES DESCRIBED DEBRIS CLOUD ABOUT 200 FEET WIDE IN LAUDING WAY. BROKEN ROOF TILES...SMALL TREES SNAPPED IN HALF...WATER SUCKED OUT FROM SWIMMING POOL.

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 CaliforniaEvery tornado in California since 1950Warnings in force in California nowThe forecast where you are

The other tornadoes of April 14, 2006

5 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
April 146:33 PM CDTF0LaSalle, IL0.525
April 147:57 PM EDTF0Benton, IN0.525
April 147:58 PM EDTF0Tippecanoe, IN3.275
April 148:18 PM EDTF1Carroll, IN2.3100$60,000
April 1410:58 PM EDTF1Decatur, IN0.8530$100,000

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.