Alert archive / Texas / Flash Flood Warnings in 2021

Flash Flood Warning 51, NWS Austin/San Antonio, TX

September 28, 2021Comal County, Hays County, Texas

NWS Austin/San Antonio, TX issued this flash flood warning at Sep 28, 2021, 11:23 PM CDT for Comal County, Hays County, Texas. It was in force for 3 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Sep 28, 2021, 11:23 PM CDT (04:23 UTC)
Expired: Sep 29, 2021, 2:30 AM CDT
In force: 3 hr
Issued by: NWS Austin/San Antonio, TX
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Comal County, TX, Hays County, TX

The radar

The Austin/San Antonio radar (KEWX), 31 km from the middle of the area, began a volume at 04:23 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

Time	Report	Where	Remark
Sep 29, 2:00 AM CDT	FLASH FLOOD	1 Sw Wimberley, TX	A LOW WATER CROSSING STREAM GAUGE INDICATED WATER OVER THE ROAD ON CR 1492 AT THE BLANCO RIVER.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Del Rio, TX (KDRT), launched 00:00Z, 4.4 hours before the alert went out and 263 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 1438 J/kg
Mixed-layer CIN: -118 J/kg
Mixed-layer LCL: 1769 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: -3 m²/s²
0-3 km storm-relative helicity: 45 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

640 
WGUS54 KEWX 290423
FFWEWX
TXC091-209-290730-
/O.NEW.KEWX.FF.W.0051.210929T0423Z-210929T0730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
1123 PM CDT Tue Sep 28 2021

The National Weather Service in Austin/San Antonio has issued a

* Flash Flood Warning for...
  Northeastern Comal County in south central Texas...
  Central Hays County in south central Texas...

* Until 230 AM CDT.

* At 1123 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 5 inches of rain 
  have fallen from Spring Branch and Canyon Lake to Wimberley and 
  Dripping Springs. Additional rainfall amounts of 1 to 3 inches are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  Kyle, Wimberley, Canyon Lake Dam, Canyon Lake, Bulverde, 
  Woodcreek, Fischer, Smithson Valley, Spring Branch, Sattler, 
  Startzville and Hays City.

This includes the following streams and drainages...
  West Fork Dry Comal Creek, Onion Creek, Spring Branch, Halifax 
  Creek, Mustang Branch, Lone Man Creek, Blanco River, York Creek, 
  Cypress Creek, Purgatory Creek, Yorks Creek, Swine Creek, 
  Guadalupe River, Bear Creek, Cedar Fork, Plum Creek, Sink Creek, 
  Dry Comal Creek, Carpers Creek, Elm Creek, Mountain Creek, Sorrel 
  Creek, Rebecca Creek, Schultz Creek, Lewis Creek, Dry Bear Creek 
  and Isaac Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3006 9815 3009 9804 3009 9796 3003 9790
      3001 9790 2985 9807 2983 9811 2980 9823
      2979 9833 2980 9840 2985 9843 2991 9842
      2995 9838 2996 9836 2994 9837

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

CP

3 follow-up statements

453 
WGUS74 KEWX 290438
FFSEWX

Flash Flood Statement
National Weather Service Austin/San Antonio TX
1138 PM CDT Tue Sep 28 2021

TXC091-209-290730-
/O.CON.KEWX.FF.W.0051.000000T0000Z-210929T0730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Comal TX-Hays TX-
1138 PM CDT Tue Sep 28 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 230 AM CDT WEDNESDAY 
FOR NORTHEASTERN COMAL AND CENTRAL HAYS COUNTIES...

At 1138 PM CDT, Doppler radar indicated thunderstorms producing 
heavy rain across the warned area. Between 2 and 5 inches of rain 
have fallen from the Spring Branch and Canyon Lake areas to 
Wimberley and Dripping Springs areas. Additional rainfall amounts of 
1 to 3 inches are possible in the warned area. Flash flooding is 
ongoing or expected to begin shortly.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  Kyle, Wimberley, Canyon Lake Dam, Canyon Lake, Bulverde, 
  Woodcreek, Fischer, Smithson Valley, Spring Branch, Sattler, 
  Startzville and Hays City.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3006 9815 3009 9804 3009 9796 3003 9790
      3001 9790 2985 9807 2983 9811 2980 9823
      2979 9833 2980 9840 2985 9843 2991 9842
      2995 9838 2996 9836 2994 9837

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

CP

112 
WGUS74 KEWX 290532
FFSEWX

Flash Flood Statement
National Weather Service Austin/San Antonio TX
1232 AM CDT Wed Sep 29 2021

TXC091-209-290730-
/O.CON.KEWX.FF.W.0051.000000T0000Z-210929T0730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Comal TX-Hays TX-
1232 AM CDT Wed Sep 29 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 230 AM CDT EARLY THIS 
MORNING FOR NORTHEASTERN COMAL AND CENTRAL HAYS COUNTIES...

At 1232 AM CDT, Doppler radar indicated thunderstorms producing 
light to moderate rain across the warned area. Rain gauges and radar 
estimates show between 2 and almost 6 inches of rain have fallen 
from Canyon Lake to Fischer to Wimberley and Woodcreek. Additional 
rainfall amounts up to 1/4 inch are possible in the warned area. 
Flash flooding is ongoing or expected to begin shortly.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  Kyle, Wimberley, Canyon Lake Dam, Canyon Lake, Bulverde, 
  Woodcreek, Fischer, Smithson Valley, Spring Branch, Sattler, 
  Startzville and Hays City.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3006 9815 3009 9804 3009 9796 3003 9790
      3001 9790 2985 9807 2983 9811 2980 9823
      2979 9833 2980 9840 2985 9843 2991 9842
      2995 9838 2996 9836 2994 9837

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

CP

870 
WGUS74 KEWX 290607
FFSEWX

Flash Flood Statement
National Weather Service Austin/San Antonio TX
107 AM CDT Wed Sep 29 2021

TXC091-209-290730-
/O.CON.KEWX.FF.W.0051.000000T0000Z-210929T0730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Comal TX-Hays TX-
107 AM CDT Wed Sep 29 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 230 AM CDT EARLY THIS 
MORNING FOR NORTHEASTERN COMAL AND CENTRAL HAYS COUNTIES...

At 107 AM CDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 3 and 6 inches of rain have 
fallen. Only light rains are expected over through 230 AM.  However, 
because of several reports of 4 to 6 inches over the area, flash 
flooding likely to continue over parts of Comal and Hays counties 
through 230 AM.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  Kyle, Wimberley, Canyon Lake Dam, Canyon Lake, Bulverde, 
  Woodcreek, Fischer, Smithson Valley, Spring Branch, Sattler, 
  Startzville and Hays City.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3006 9815 3009 9804 3009 9796 3003 9790
      3001 9790 2985 9807 2983 9811 2980 9823
      2979 9833 2980 9840 2985 9843 2991 9842
      2995 9838 2996 9836 2994 9837

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

MO

The office that day

Everything else NWS Austin/San Antonio, TX issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 28, 7:01 PM CDT	Special Weather Statement	EWX	Gonzales	44 min
Sep 28, 7:34 PM CDT	Special Weather Statement	EWX	Mason	26 min
Sep 28, 7:45 PM CDT	Severe Thunderstorm Warning	EWX	Williamson	37 min
Sep 28, 7:57 PM CDT	Special Weather Statement	EWX	Travis	48 min
Sep 28, 8:43 PM CDT	Areal Flood Advisory	EWX	Travis, Williamson	3 hr
Sep 28, 8:44 PM CDT	Areal Flood Advisory	EWX	Gillespie	4 hr
Sep 28, 9:04 PM CDT	Areal Flood Advisory	EWX	Zavala	3 hr
Sep 28, 9:10 PM CDT	Areal Flood Advisory	EWX	Williamson	3 hr
Sep 28, 9:12 PM CDT	Special Weather Statement	EWX	Bexar	48 min
Sep 28, 9:29 PM CDT	Special Weather Statement	EWX	Bandera	46 min
Sep 28, 9:40 PM CDT	Special Weather Statement	EWX	Hays	50 min
Sep 28, 9:47 PM CDT	Areal Flood Advisory	EWX	Lee, Travis, Williamson	3 hr
Sep 28, 9:52 PM CDT	Areal Flood Advisory	EWX	Bexar	3 hr
Sep 28, 9:58 PM CDT	Areal Flood Advisory	EWX	Comal, Hays, Kendall, Travis	3 hr
Sep 28, 10:10 PM CDT	Special Weather Statement	EWX	Kendall	50 min
Sep 28, 10:13 PM CDT	Areal Flood Advisory	EWX	Bandera	3 hr
Sep 28, 10:20 PM CDT	Special Weather Statement	EWX	Kendall	40 min
Sep 28, 10:40 PM CDT	Special Weather Statement	EWX	Kerr	50 min
Sep 28, 11:09 PM CDT	Special Weather Statement	EWX	Comal	51 min
Sep 28, 11:19 PM CDT	Special Weather Statement	EWX	Comal, Guadalupe	41 min
Sep 28, 11:36 PM CDT	Areal Flood Advisory	EWX	Bastrop, Caldwell, Comal, Guadalupe, Hays, Travis	3 hr
Sep 28, 11:49 PM CDT	Flash Flood Warning Considerable damage threat	EWX	Caldwell, Comal, Guadalupe, Hays	5 hr
Sep 29, 12:27 AM CDT	Special Weather Statement	EWX	Gonzales	48 min
Sep 29, 12:37 AM CDT	Areal Flood Advisory	EWX	Bastrop, Caldwell, Fayette, Gonzales, Guadalupe, Lee	3 hr
Sep 29, 12:43 AM CDT	Areal Flood Advisory	EWX	Bexar, Comal, Gonzales, Guadalupe	3 hr
Sep 29, 1:23 AM CDT	Flash Flood Warning Considerable damage threat	EWX	Bexar, Comal, Guadalupe	4 hr
Sep 29, 1:34 AM CDT	Areal Flood Advisory	EWX	Gillespie	3 hr
Sep 29, 2:05 AM CDT	Areal Flood Advisory	EWX	DeWitt, Fayette, Gonzales, Karnes, Lavaca, Wilson	4 hr
Sep 29, 2:28 AM CDT	Special Weather Statement	EWX	Blanco	47 min
Sep 29, 3:00 AM CDT	Special Weather Statement	EWX	Kerr	45 min
Sep 29, 3:21 AM CDT	Severe Thunderstorm Warning	EWX	Gillespie, Kerr, Real	42 min
Sep 29, 3:44 AM CDT	Special Weather Statement	EWX	Bandera	46 min
Sep 29, 4:15 AM CDT	Areal Flood Advisory	EWX	Bandera, Kendall, Kerr	4 hr
Sep 29, 6:25 AM CDT	Areal Flood Advisory	EWX	Bandera, Bexar, Medina	3 hr

Nearby

Flash Flood Warnings in Texas, 2021 Every flash flood warning in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.