Tornadoes · United States · Texas · 2001
F0 tornado, Willis, Texas, December 16, 2001
This F0 tornado ran 0.1 miles across Montgomery County on December 16, 2001, touching down at 7:44 PM CST and reaching 70 yards wide. It killed nobody, and did $30,000 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.
F040 to 72 mphthis tornado
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
F173 to 112 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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.
F4207 to 260 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
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
- F0
- Date
- December 16, 2001
- Touchdown
- 7:44 PM CST (01:44 UTC)
- Path length
- 0.1 miles (0.2 km)
- Path width
- 70 yards (64 m)
- Deaths
- 0
- Injuries
- 0
- Property damage
- $30,000
- County
- Montgomery County
- Touchdown point
- 30.420, -95.480
- Lift-off point
- 30.420, -95.480
- Record number
- 587
What the Weather Service recorded
An F0 Tornado touched down in Willis, along Montgomery Street, on FM 1097. Trees were uprooted, power lines were snapped with power outages in town, and there was minor roof damage to some homes. There were no injuries. Reported by Sheriff and public.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The warnings
39 minutes of warning. NWS HGX issued a tornado warning for this county at 01:05 UTC, 39 minutes before the tornado touched down, in force until 02:00 UTC.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 22:52 UTC | 23:30 UTC | Tornado Warning | HGX |
| 01:05 UTC | 02:00 UTC | Tornado Warning | HGX |
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. The outlook in force was issued at 01:08 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.
What forecasters said that day
The local office's own words before the tornado touched down, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Houston/Galveston, TX wrote its last area forecast discussion before the tornado touched down at Dec 16, 2:28 PM CST, 5 hours 16 minutes earlier.
Area forecast discussion, Dec 16, 2:28 PM CST, 5 hours 16 minutes before
SOUTHEAST TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
228 PM CST SUN DEC 16 2001
SHOWER AND THUNDERSTORM COVERAGE AND INTENSITY HAS BEGUN TO INCREASE
ACROSS PORTIONS OF SOUTHEAST TEXAS THIS AFTERNOON. AT THIS TIME...
THE GREATEST CONCENTRATION IS STILL UP IN FTWS COUNTY WARNING AREA
WHERE THE BEST TRAINING IS OCCURRING. AS THE UPPER LOW NOW OUT IN
WEST TEXAS CONTINUES TO MOVE TO THE EAST...MID AND UPPER LEVEL
FORCING IS EXPECTED TO INCREASE ACROSS OUR AREA...ESPECIALLY IN OUR
NORTHERN ZONES CLOSER TO THE WARM FRONTAL BOUNDARY. THIS WILL RESULT
IN A GREATER THREAT FOR SEVERE THUNDERSTORMS DUE TO PRETTY DECENT
SHEAR. STILL THINK WE CAN GET SOME SEVERE THUNDERSTORMS TO DEVELOP
BEHIND THE MAIN SQUALL LINE THAT IS EXPECTED TO DEVELOP LATER THIS
AFTERNOON AND THIS EVENING. LAPSE RATES WILL BE STEEPENING AS THE
UPPER LOW PROGRESSES CLOSER TO OUR AREA...AND OUR EXTREMELY MOIST
AND UNSTABLE AIRMASS MAY BECOME MORE SUPPORTIVE OF SEVERE STORMS.
WILL KEEP THE MENTION OF SEVERE STORMS AND LOCALLY HEAVY RAINFALL IN
ALL ZONES FOR TONIGHT. SEVERE THREAT WILL BE GONE BY MORNING...BUT
IT IS STILL POSSIBLE SOME SHOWERS MAY LINGER ACROSS THE AREA AROUND
AND SHORTLY AFTER SUNRISE. AFTER MONDAY...DO NOT EXPECT THE RETURN
FLOW TO BE SUFFICIENT FOR ANY POPS WITH THE NEXT FRONTAL PASSAGE ON
WEDNESDAY. THIS FRONT WILL REINFORCE OUR COOL NIGHTS AND MILD DAYS.
THEN BEGINNING ON FRIDAY...A RETURN FLOW DOES BEGIN AS THE NEXT
UPPER LOW DEVELOPS OUT WEST. THERE IS MUCH UNCERTAINTY AS TO HOW
STRONG/HOW DEEP/HOW FAST THIS NEXT UPPER LOW WILL BE. FOR NOW...WILL
CONTINUE TO CALL FOR MOSTLY CLOUDY SKIES AND A CHANCE OF SHOWERS AND
THUNDERSTORMS FRIDAY THROUGH SUNDAY. LOOKS LIKE A MUCH COLDER AND
DRIER AIRMASS MIGHT BE HERE IN TIME FOR THE WEEK OF CHRISTMAS.
42/35/39
.HGX...TORNADO WATCH IN EFFECT TIL 7 PM FOR NORTHERN COUNTIES.
SCA ALL WATERS TONIGHT.
PRELIMS...
CLL BU 048/063 038/066 042 810
IAH BU 052/064 040/066 042 820
GLS BU 057/062 048/064 052 830In the hours before
Special weather statement, Dec 16, 2:00 PM CST, 5 hours 44 minutes before
TXZ163-164-176-177-198-170100- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 200 PM CST SUN DEC 16 2001 ...TORNADO WATCH IN EFFECT UNTIL 700 PM CST... A TORNADO WATCH IS IN EFFECT FOR PARTS OF SOUTHEAST TEXAS UNTIL 700 PM THIS EVENING. THE WATCH COVERS PARTS OF EAST TEXAS...IN THE VICINITY OF A WARM FRONT...NEAR WHICH THUNDERSTORMS ARE EXPECTED TO INTENSIFY. THE FOLLOWING COUNTIES ARE INCLUDED IN THE WATCH...GRIMES... HOUSTON...MADISON...TRINITY...AND WALKER. THUNDERSTORMS HAVE BEGUN DEVELOPING ACROSS PORTIONS OF EAST TEXAS... IN ADVANCE OF AN APPROACHING UPPER-LEVEL TROUGH. THE INCREASED LIFT ASSOCIATED WITH THE TROUGH SHOULD ALLOW THE STORMS TO INCREASE IN INTENSITY AND AREAL COVERAGE. THE SURFACE FRONT...STRONG LOW-LEVEL WINDS...THE MOVEMENT OF THE UPPER TROUGH...AS WELL AS THE SHEAR RESULTING FROM THESE FEATURES...WILL CREATE AN ENVIRONMENT FAVORABLE FOR ROTATING STORMS. SOME OF THE THUNDERSTORMS TO THE WEST HAVE ALREADY SHOWN SIGNS OF ROTATION. THIS MEANS SEVERE THUNDERSTORMS...CAPABLE OF PRODUCING TORNADOES... ARE POSSIBLE...IN AND NEAR THE WATCH AREA. BE ALERT FOR DAMAGING WINDS AND LARGE HAIL IN THUNDERSTORMS THIS AFTERNOON. IF YOU ARE IN THE PATH OF A SEVERE THUNDERSTORM OR TORNADO...MOVE INSIDE TO A REINFORCED STRUCTURE AWAY FROM WINDOWS. REPORT DAMAGING WINDS AND LARGE HAIL TO LOCAL LAW ENFORCEMENT...AND ASK THEM TO RELAY THE MESSAGE TO THE NATIONAL WEATHER SERVICE. ALSO BE ALERT FOR HEAVY RAIN THAT WILL CAUSE HIGH STANDING WATER ON ROADS AND IN AREAS OF POOR DRAINAGE. DO NOT DRIVE INTO AREAS WITH HIGH WATER. A COLD FRONT WILL PASS THROUGH THE REGION TONIGHT...ENDING THE PRECIPITATION. DRIER AND COOLER WEATHER WILL ACCOMPANY THE ARRIVAL OF THE WORKWEEK. 39
Special weather statement, Dec 16, 6:31 PM CST, 1 hour 13 minutes before
GMZ335-TXZ163-164-176>179-195>200-210>214-227-238-170500- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 631 PM CST SUN DEC 16 2001 A TORNADO WATCH HAS BEEN ISSUED FOR FOR THE NORTHERN PORTIONS OF SOUTHEAST TEXAS...GENERALLY ALONG AND NORTH OF A LINE FROM COLUMBUS TO RICHMOND TO HOUSTON TO GALVESTON. THE TORNADO WATCH WILL BE IN EFFECT TILL 11 PM. WHEN THUNDERSTORMS ARE OCCURRING...MOVE INDOORS. DO NOT STAND BY WINDOWS. UNLESS IT IS AN EMERGENCY...AVOID USING TELEPHONES AND ELECTRICAL APPLIANCES UNTIL THE STORM HAS PASSED. DAMAGING WIND... LARGE HAIL...ISOLATED BRIEF TORNADOES AND VERY HEAVY RAIN ARE POSSIBLE IN SEVERE THUNDERSTORMS. REMEMBER A WATCH MEANS CONDITIONS ARE FAVORABLE FOR THE DEVELOPMENT SEVERE WEATHER...A WARNING MEANS SEVERE WEATHER IS IMMINENT OR ALREADY OCCURRING. THE FOLLOWING COUNTIES ARE IN THE WATCH. HOUSTON...TRINITY...POLK... MADISON...TYLER...WALKER...BRAZOS...SAN JACINTO...GRIMES...BURLESON... MONTGOMERY...LIBERTY...WASHINGTON...WALLER...HARRIS...AUSTIN... COLORADO...FORT BEND...GALVESTON...AND CHAMBERS. RESIDENTS ACROSS SOUTHEAST TEXAS ARE STRONGLY URGED TO MONITOR NOAA WEATHER RADIO AND LOCAL NEWS SOURCES AND BE PREPARED TO TAKE ACTION IN CASE WARNINGS ARE ISSUED.
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.
Lake Charles Mun, LA (KLCH), 00:00Z
1.7 hours before the tornado, 221 km from the path. December 17, 2001.
- Mixed-layer CAPE
- 1068 J/kg
- Mixed-layer CIN
- -3 J/kg
- Surface CAPE
- 1105 J/kg
- Mixed-layer LCL
- 531 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- 169 m²/s²
- 0-3 km storm-relative helicity
- 178 m²/s²
- Significant tornado parameter
- 1.1
- Supercell composite
- 6.2
- 0-3 km lapse rate
- 5.8 K/km
Lake Charles Mun, LA (KLCH), 12:00Z
10.3 hours after it, 221 km from the path. December 17, 2001.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- -84666 J/kg
- Surface CAPE
- 3 J/kg
- Mixed-layer LCL
- 743 m above ground
- 0-6 km bulk shear
- 56 kt
- 0-1 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- -125 m²/s²
- 0-3 km storm-relative helicity
- -169 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
- 0-3 km lapse rate
- 3.2 K/km
The surface observations
Conroe/Montgomery County Airport (CXO), 10 km from the path, in the two hours either side.
| Time (UTC) | Temp (°F) | Dew point (°F) | Wind | Gust (kt) | Pressure (mb) | Weather |
|---|---|---|---|---|---|---|
| 23:53 UTC | 75 | 71 | 170° 14 kt | 1008.5 | ||
| 00:53 UTC | 75 | 72 | 180° 14 kt | 1008.5 | ||
| 01:27 UTC | 73.4 | 71.6 | 200° 13 kt | 21 | 1009.5 | VCTS +RA BR |
| 01:46 UTC | 73.4 | 71.6 | 210° 9 kt | 19 | 1008.8 | -RA BR |
| 01:53 UTC | 73 | 71 | 220° 13 kt | 18 | 1009.8 | VCTS -RA |
| 02:01 UTC | 68 | 64.4 | 280° 20 kt | 28 | 1010.5 | VCTS RA |
| 02:09 UTC | 66.2 | 64.4 | 290° 16 kt | 22 | 1010.8 | +RA BR |
| 02:17 UTC | 66.2 | 62.6 | 290° 14 kt | 21 | 1010.8 | +RA BR |
| 02:53 UTC | 65 | 62 | 310° 11 kt | 1011.5 | -RA |
From the Iowa Environmental Mesonet's archive of airport observations.
The radar
The Houston radar (KHGX), 112 km away, was scanning. The volume nearest the touchdown began at 01:41 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.
This ground now
The live radar over the trackEvery 2001 tornado in TexasEvery tornado in Texas since 1950Warnings in force in Texas nowThe forecast where you are
The other tornadoes of December 16, 2001
2 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| December 16 | 5:29 PM CST | F2 | San Jacinto, TX | 3.0 | 200 | 2 | $2.5 million | |
| December 16 | 5:32 PM CST | F0 | Gregg, TX | 1.4 | 25 |
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.