Alert archive / Virginia / Flash Flood Warnings in 2021

Flash Flood Warning 18, NWS Blacksburg, VA

July 11, 2021Grayson County, Virginia

NWS Blacksburg, VA issued this flash flood warning at Jul 11, 2021, 5:38 PM EDT for Grayson County, Virginia. It was in force for 3 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: Jul 11, 2021, 5:38 PM EDT (21:38 UTC)
Expired: Jul 11, 2021, 8:08 PM EDT
In force: 3 hr
Issued by: NWS Blacksburg, VA
Area: Storm-based polygon
Flood severity: None

County Grayson County, VA

The radar

The Roanoke radar (KFCX), 102 km from the middle of the area, began a volume at 21:40 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

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 9.6 hours before the alert went out and 141 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: 536 J/kg
Mixed-layer CIN: -25 J/kg
Mixed-layer LCL: 923 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 42 m²/s²
0-3 km storm-relative helicity: 52 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

748 
WGUS51 KRNK 112138
FFWRNK
VAC077-120030-
/O.NEW.KRNK.FF.W.0018.210711T2138Z-210712T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Blacksburg VA
538 PM EDT Sun Jul 11 2021

The National Weather Service in Blacksburg has issued a

* Flash Flood Warning for...
  South Central Grayson County in southwestern Virginia...

* Until 830 PM EDT.

* At 538 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain between Elk Creek, Mouth of Wilson, Volney, and Grassy 
  Creek. Between 1 and 2 inches of rain have fallen. Additional 
  rainfall amounts of 1 to 1.5 inches are possible in the warned 
  area. Flash flooding has been reported by the public.

  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...
  Independence...                    Mouth Of Wilson...
  Bridle Creek...                    Volney...
  Elk Creek...

This includes the following streams and drainages...
  Mill Creek, Middle Fox Creek, Elk Creek, Fox Creek, Grassy Creek, 
  Guffey Creek, Flag Pond Branch, Little Peach Bottom Creek, Bridle 
  Creek, Little Wilson Creek, Farmers Branch, Beaverdam Creek, Brush 
  Creek, Middle Branch Elk Creek, Bear Branch and Comers Rock Branch.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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.

Flooding is occurring or is imminent. It is important to know where 
you are relative to streams, rivers, or creeks which can become 
killers in heavy rains. Campers and hikers should avoid streams or 
creeks.

When it is safe to do so, please send your reports of flooding, 
including mudslides or flooded roads, to the National Weather 
Service by calling toll free at 1...8 6 6...2 1 5...4 3 2 4. Reports 
and pictures can also be shared on the National Weather Service 
Blacksburg Facebook page and on Twitter.

&&

LAT...LON 3658 8142 3665 8145 3665 8143 3667 8137
      3672 8126 3672 8119 3669 8117 3663 8114
      3657 8128

FLASH FLOOD...RADAR INDICATED

$$

RAB

2 follow-up statements

203 
WGUS71 KRNK 112304
FFSRNK

Flash Flood Statement
National Weather Service Blacksburg VA
704 PM EDT Sun Jul 11 2021

VAC077-120030-
/O.CON.KRNK.FF.W.0018.000000T0000Z-210712T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Grayson VA-
704 PM EDT Sun Jul 11 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 830 PM EDT THIS 
EVENING FOR SOUTH CENTRAL GRAYSON COUNTY...

At 704 PM EDT, Rainfall has diminished within the warned area. 
However, from 1.5 to 2.0 inches of rain fell across parts of 
southern Grayson county during the past couple of hours. With steep 
and rugged terrain in this area, such heavy rainfall will quickly 
result in flooding of small creeks and streams and water rushing 
down from the higher terrain.  Flooding remains a possibility 
throughout the warned area.

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...
  Independence...                    Mouth Of Wilson...
Bridle Creek...                    Volney...
Elk Creek...

This includes the following streams and drainages...
  Mill Creek, Middle Fox Creek, Elk Creek, Fox Creek, Grassy Creek, 
  Guffey Creek, Flag Pond Branch, Little Peach Bottom Creek, Bridle 
  Creek, Little Wilson Creek, Farmers Branch, Beaverdam Creek, Brush 
  Creek, Middle Branch Elk Creek, Bear Branch and Comers Rock Branch.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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.

Flooding is occurring or is imminent. It is important to know where 
you are relative to streams, rivers, or creeks which can become 
killers in heavy rains. Campers and hikers should avoid streams or 
creeks.

When it is safe to do so, please send your reports of flooding, 
including mudslides or flooded roads, to the National Weather 
Service by calling toll free at 1...8 6 6...2 1 5...4 3 2 4. Reports 
and pictures can also be shared on the National Weather Service 
Blacksburg Facebook page and on Twitter.

&&

LAT...LON 3658 8142 3665 8145 3665 8143 3667 8137
      3672 8126 3672 8119 3669 8117 3663 8114
      3657 8128

FLASH FLOOD...RADAR INDICATED

$$

RAB

514 
WGUS71 KRNK 120008
FFSRNK

Flash Flood Statement
National Weather Service Blacksburg VA
808 PM EDT Sun Jul 11 2021

VAC077-120018-
/O.CAN.KRNK.FF.W.0018.000000T0000Z-210712T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Grayson VA-
808 PM EDT Sun Jul 11 2021

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTH CENTRAL GRAYSON 
COUNTY...

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

LAT...LON 3658 8142 3665 8145 3665 8143 3667 8137
      3672 8126 3672 8119 3669 8117 3663 8114
      3657 8128

$$

RAB

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 10, 8:32 PM EDT	Special Weather Statement	RNK	Carroll, Giles, Pulaski, City of Galax	58 min
Jul 10, 10:07 PM EDT	Areal Flood Advisory	RNK	Craig, Floyd, Giles, Montgomery, Pulaski, Roanoke and 1 more	113 min
Jul 10, 10:22 PM EDT	Special Weather Statement	RNK	Patrick	23 min
Jul 10, 10:49 PM EDT	Special Weather Statement	RNK	Floyd, Franklin, Henry, Patrick	56 min
Jul 11, 12:20 AM EDT	Special Weather Statement	RNK	City of Roanoke, City of Salem	55 min
Jul 11, 11:21 AM EDT	Special Weather Statement	RNK	Halifax	24 min
Jul 11, 11:43 AM EDT	Severe Thunderstorm Warning	RNK	Halifax	62 min
Jul 11, 11:53 AM EDT	Special Weather Statement	RNK	City of Martinsville	37 min
Jul 11, 12:24 PM EDT	Special Weather Statement	RNK	City of Danville	36 min
Jul 11, 12:42 PM EDT	Special Weather Statement	RNK	Charlotte	33 min
Jul 11, 12:46 PM EDT	Special Weather Statement	RNK	Pittsylvania, City of Danville	44 min
Jul 11, 1:10 PM EDT	Special Weather Statement	RNK	Charlotte	35 min
Jul 11, 1:38 PM EDT	Severe Thunderstorm Warning	RNK	Campbell, Halifax, Pittsylvania	67 min
Jul 11, 2:34 PM EDT	Special Weather Statement	RNK	City of Lynchburg	26 min
Jul 11, 2:43 PM EDT	Special Weather Statement	RNK	Charlotte	32 min
Jul 11, 2:56 PM EDT	Special Weather Statement	RNK	Carroll	34 min
Jul 11, 3:27 PM EDT	Special Weather Statement	RNK	Grayson, Wythe	48 min
Jul 11, 5:17 PM EDT	Flash Flood Warning	RNK	Grayson, Smyth, Wythe	3 hr
Jul 11, 5:45 PM EDT	Special Weather Statement	RNK	Pulaski, City of Radford	60 min
Jul 11, 6:02 PM EDT	Special Weather Statement	RNK	Carroll, City of Galax	58 min
Jul 11, 6:12 PM EDT	Flash Flood Warning	RNK	Carroll, Grayson, City of Galax	3 hr
Jul 11, 6:30 PM EDT	Special Weather Statement	RNK	Bath	60 min
Jul 11, 6:47 PM EDT	Severe Thunderstorm Warning	RNK	Bath	58 min

Nearby

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