Flash Flooding in Texas, September 5, 2001

Name: Flash Flooding in Texas, September 5, 2001
Start: 2001-09-05T10:00
End: 2001-09-05T16:00
Location: Texas

September 5, 2001 · NWS EWX · 4 events in 4 counties and zones

Where it happened

Every event with a place to put it; 4 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: $30,000
Crop damage: None recorded
Events: 4

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS EWX wrote it up.

With soils over Lavaca and DeWitt Counties still saturated from heavy rainfall in the past two days, flash flooding redeveloped very quickly near noon times as showers and thunderstorms formed in Lavaca County and spread into DeWitt County. General rain amounts were 1 to 2 inches. The rain spread into Karnes and Gonzales Counties in the early afternoon, with rain totals over those two counties near 2 inches. Flash flooding developed quickly and dissipated in the late afternoon.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Austin/San Antonio, TX wrote its last area forecast discussion before the first event at Sep 5, 2:30 AM CST, 7 hours 30 minutes earlier.

Area forecast discussion, Sep 5, 2:30 AM CST, 7 hours 30 minutes before

SOUTH CENTRAL TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
330 AM CDT WED SEP 5 2001

UPPER LEVEL LOW OVER TX TO WEAKEN THROUGH THURSDAY AND WITH VIGOROUS
UPPER TROUGH OVER THE PACIFIC NORTHWEST EXPECTED TO PUSH SOUTHEAST
APPROACHING SOUTHERN PLAINS LATE FRIDAY...THIS WILL ALLOW MORE DRIER
AIR ALOFT TO BE ADVECTED IN FROM THE WEST AND ALSO LOWER LOW LEVEL
CONVERGENT AIRMASS POSSIBILITIES (OTHER THAN SEA BREEZE TYPE
FRICTIONAL EFFECTS ALONG THE COASTAL REGIONS INTO SOUTHEAST
PORTIONS)...AS AN INCREASING SOUTHERLY FLOW WILL RESULT.  AS LONG AS
THE UPPER LOW PERSISTS WITH RELATIVELY DEEP ATMOSPHERIC MOISTURE...
WELL HAVE THE CHANCE FOR SCATTERED MOSTLY AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS.  WELL KEEP THE FLASH FLOOD WATCH IN THE
FORECAST THROUGH TONIGHT AS GOOD CHANCES OF RAIN ARE FORECAST.  THE
DEFINED AREA FROM THE LAST ISSUANCE STILL LOOKS GOOD AND WELL GO
WITH IT.  FLASH FLOOD GUIDANCE VALUES STILL ARE QUITE LOW WITH MANY
COUNTIES IN THE WATCH AREA SHOWING THEY NEED ONLY AN INCH OR LESS IN
AN HOURS TIME TO PRODUCE FLOODING.

RIDGING BUILDS ACROSS AREA IN THE EXTENDED PERIODS BUT WITH SO MUCH
SURFACE BASED MOISTURE AVAILABLE...WELL LEAVE SLIGHT CHANCES TO
ISOLATEDS IN FORECAST.  SEA BREEZE MAY GET GOING TO BY THE WEEKEND.
OPEN WAVE FORECAST TO PUSH INLAND ALONG LOWER COAST BY TUESDAY...
BREAKING UP IN MEXICO BUT SOME OF MOISTURE AND INSTABILITY FROM IT
MAY ADVECT NORTHWARD INTO SOUTH CENTRAL TEXAS BY MIDWEEK.

PRELIMINARY NUMBERS...
AUS 89/70/90/71 4542
DRT 91/70/92/71 5542
SAT 89/71/90/71 5543

.EWX...FLASH FLOOD WATCH TODAY AND TONIGHT EAST HALF OF SOUTH
CENTRAL TEXAS.

The radar

The Austin/San Antonio radar (KEWX), 112 km away, was scanning. The volume nearest the first event began at 15:58 UTC.

Open the radar archive at this moment

Event by event

4 flash flood. Local standard time, as filed.

Flash Flood, Lavaca

When: September 5, 10:00 AM CST to 1:00 PM CST
Where: Lavaca County, Countywide
Property damage: $10,000
Reported by: LAW ENFORCEMENT
Coordinates: 29.384, -96.930 (the zone’s center; the record gives no point)

Flash Flood, De Witt

When: September 5, 11:00 AM CST to 2:00 PM CST
Where: De Witt County, Countywide
Property damage: $10,000
Reported by: LAW ENFORCEMENT
Coordinates: 29.082, -97.357 (the zone’s center; the record gives no point)

Flash Flood, Gonzales

When: September 5, 12:00 PM CST to 4:00 PM CST
Where: Gonzales County, West Portion
Property damage: $5,000
Reported by: LAW ENFORCEMENT
Coordinates: 29.457, -97.492 (the zone’s center; the record gives no point)

Flash Flood, Karnes

When: September 5, 1:15 PM CST to 4:00 PM CST
Where: Karnes County, North Portion
Property damage: $5,000
Reported by: LAW ENFORCEMENT
Coordinates: 28.906, -97.859 (the zone’s center; the record gives no point)

What these are

Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Texas in 2001 Every state in 2001 This day in weather history Warnings in Texas, September 2001

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 5266143, 5266182, 5266183, 5266184.