Alert archive / Virginia / Flash Flood Warnings in 2021

Flash Flood Warning 34, NWS Blacksburg, VA

August 31, 2021Botetourt County, Craig County, Roanoke County, Virginia

NWS Blacksburg, VA issued this flash flood warning at Aug 31, 2021, 9:44 PM EDT for Botetourt County, Craig County, Roanoke County, Virginia. It was in force for 5 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 31, 2021, 9:44 PM EDT (01:44 UTC)
Expired
Sep 1, 2021, 3:04 AM EDT
In force
5 hr
Issued by
NWS Blacksburg, VA
Area
Storm-based polygon
Flood severity
None

Counties Botetourt County, VA, Craig County, VA, Roanoke County, VA

The radar

The Roanoke radar (KFCX), 53 km from the middle of the area, began a volume at 01:48 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.

The nearest sounding before it

Roanoke, VA (KRNK), launched 00:00Z, 1.7 hours before the alert went out and 58 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-pSkew-T log-p diagram, Roanoke, VA at 00:00Z on 2021-09-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 319 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Roanoke, VA at 00:00Z on 2021-09-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 122 square meters per square second.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.
Mixed-layer CAPE
319 J/kg
Mixed-layer CIN
-23 J/kg
Mixed-layer LCL
782 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
122 m²/s²
0-3 km storm-relative helicity
133 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.9

Open this sounding in Storm Lab

The text

As transmitted.

015 
WGUS51 KRNK 010144
FFWRNK
VAC023-045-161-010745-
/O.NEW.KRNK.FF.W.0034.210901T0144Z-210901T0745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Blacksburg VA
944 PM EDT Tue Aug 31 2021

The National Weather Service in Blacksburg has issued a

* Flash Flood Warning for...
  Eastern Craig County in southwestern Virginia...
  Southwestern Botetourt County in west central Virginia...
  Northwestern Roanoke County in west central Virginia...

* Until 345 AM EDT Wednesday.

* At 944 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 3.5 inches of 
  rain have fallen. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Salem...                           New Castle...
  Catawba...                         Oriskany...
  Abbott...

This includes the following streams and drainages...
  Barbours Creek, Broad Run, Bens Run, Blue Spring Run, Big Bear 
  Rock Branch, Carvin Creek and Catawba Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3742 8019 3760 8015 3765 8004 3765 8002
      3769 7995 3758 7989 3745 7997 3736 7998
      3731 8003 3732 8003 3728 8015 3734 8018

FLASH FLOOD...RADAR INDICATED

$$

16
3 follow-up statements
411 
WGUS71 KRNK 010159
FFSRNK

Flash Flood Statement
National Weather Service Blacksburg VA
959 PM EDT Tue Aug 31 2021

VAC023-045-161-010745-
/O.CON.KRNK.FF.W.0034.000000T0000Z-210901T0745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Botetourt VA-Craig VA-Roanoke VA-
959 PM EDT Tue Aug 31 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 345 AM EDT WEDNESDAY 
FOR EASTERN CRAIG, SOUTHWESTERN BOTETOURT AND NORTHWESTERN ROANOKE 
COUNTIES...

At 959 PM EDT, Doppler radar indicated thunderstorms produced 
between 2 and 3.5 inches of rain since about 845 pm. Additional 
rainfall amounts up to 0.5 inch is possible in the warned area. 
Runoff from this rain will accumulate rapidly in local creeks and 
rivers, causing them to overflow their banks. Flash flooding is 
ongoing or expected to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
Salem...                           New Castle...
Catawba...                         Oriskany...
Abbott...

This includes the following streams and drainages...
  Barbours Creek, Broad Run, Bens Run, Blue Spring Run, Big Bear 
  Rock Branch, Carvin Creek and Catawba Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3742 8019 3760 8015 3765 8004 3765 8002
      3769 7995 3758 7989 3745 7997 3736 7998
      3731 8003 3732 8003 3728 8015 3734 8018

FLASH FLOOD...RADAR INDICATED

$$

16
340 
WGUS71 KRNK 010218
FFSRNK

Flash Flood Statement
National Weather Service Blacksburg VA
1018 PM EDT Tue Aug 31 2021

VAC023-045-161-010745-
/O.CON.KRNK.FF.W.0034.000000T0000Z-210901T0745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Botetourt VA-Craig VA-Roanoke VA-
1018 PM EDT Tue Aug 31 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 345 AM EDT WEDNESDAY 
FOR EASTERN CRAIG, SOUTHWESTERN BOTETOURT AND NORTHWESTERN ROANOKE 
COUNTIES...

At 1018 PM EDT, Doppler radar indicated thunderstorms producing 
heavy rain across the warned area. Between 2 and 3.5 inches of rain 
have fallen. Additional rainfall amounts up to 0.5 inches are 
possible in the warned area. Flash flooding is ongoing or expected 
to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Salem...                           New Castle...
Catawba...                         Oriskany...
Abbott...

This includes the following streams and drainages...
  Barbours Creek, Broad Run, Bens Run, Blue Spring Run, Big Bear 
  Rock Branch, Carvin Creek and Catawba Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3742 8019 3760 8015 3765 8004 3765 8002
      3769 7995 3758 7989 3745 7997 3736 7998
      3731 8003 3732 8003 3728 8015 3734 8018

FLASH FLOOD...RADAR INDICATED

$$

KK
291 
WGUS71 KRNK 010704
FFSRNK

Flash Flood Statement
National Weather Service Blacksburg VA
304 AM EDT Wed Sep 1 2021

VAC023-045-161-010714-
/O.CAN.KRNK.FF.W.0034.000000T0000Z-210901T0745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Botetourt VA-Craig VA-Roanoke VA-
304 AM EDT Wed Sep 1 2021

...FLASH FLOOD WARNING IS CANCELLED FOR EASTERN CRAIG, SOUTHWESTERN 
BOTETOURT AND NORTHWESTERN ROANOKE COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

A Flash Flood Watch remains in effect until 1200 AM EDT Thursday for 
portions of North Carolina, Virginia and southeast West Virginia.

LAT...LON 3742 8019 3760 8015 3765 8004 3765 8002
      3769 7995 3758 7989 3745 7997 3736 7998
      3731 8003 3732 8003 3728 8015 3734 8018

$$

KK

The office that day

Everything else NWS Blacksburg, VA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 31, 8:00 PM EDTAreal Flood AdvisoryRNKCraig, Floyd, Giles, Montgomery, City of Radford5 hr
Aug 31, 8:26 PM EDTSpecial Weather StatementRNKCraig, Roanoke, City of Roanoke, City of Salem34 min
Aug 31, 8:40 PM EDTAreal Flood AdvisoryRNKBedford, Botetourt, Craig, Floyd, Franklin, Montgomery and 3 more3 hr
Aug 31, 8:43 PM EDTSpecial Weather StatementRNKCraig32 min
Aug 31, 9:12 PM EDTSpecial Weather StatementRNKBotetourt33 min
Aug 31, 9:18 PM EDTSpecial Weather StatementRNKAlleghany, City of Covington27 min
Aug 31, 9:35 PM EDTTornado WarningRNKBedford, Botetourt25 min
Aug 31, 9:47 PM EDTSpecial Weather StatementRNKAlleghany, Bath, City of Covington28 min
Aug 31, 9:58 PM EDTTornado WarningRNKBedford, Botetourt, Rockbridge32 min
Aug 31, 10:26 PM EDTSpecial Weather StatementRNKRockbridge, City of Buena Vista, City of Lexington34 min
Aug 31, 10:30 PM EDTSpecial Weather StatementRNKBotetourt30 min
Aug 31, 10:32 PM EDTAreal Flood AdvisoryRNKBedford, Botetourt, Rockbridge3 hr
Aug 31, 10:44 PM EDTTornado WarningRNKAmherst, Rockbridge, City of Buena Vista31 min
Aug 31, 11:10 PM EDTAreal Flood AdvisoryRNKAmherst, Rockbridge, City of Buena Vista, City of Lexington3 hr
Aug 31, 11:17 PM EDTSpecial Weather StatementRNKCity of Buena Vista28 min
Sep 1, 12:38 AM EDTSpecial Weather StatementRNKRockbridge22 min
Sep 1, 5:29 AM EDTAreal Flood AdvisoryRNKAlleghany, Botetourt, Craig, Roanoke3 hr
Sep 1, 7:27 AM EDTSpecial Weather StatementRNKCampbell, Pittsylvania, City of Danville, City of Lynchburg48 min
Sep 1, 7:54 AM EDTSpecial Weather StatementRNKAmherst, City of Lynchburg51 min
Sep 1, 8:43 AM EDTSpecial Weather StatementRNKAmherst32 min
Sep 1, 9:17 AM EDTAreal Flood AdvisoryRNKFranklin118 min
Sep 1, 11:38 AM EDTSpecial Weather StatementRNKFloyd, Roanoke, City of Roanoke, City of Salem22 min
Sep 1, 11:59 AM EDTSpecial Weather StatementRNKCity of Roanoke, City of Salem46 min
Sep 1, 12:06 PM EDTAreal Flood AdvisoryRNKCarroll, Floyd, Franklin, Montgomery, Patrick, Roanoke and 1 more3 hr
Sep 1, 3:47 PM EDTAreal Flood AdvisoryRNKPatrick2 hr

Nearby

Flash Flood Warnings in Virginia, 2021Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.