Alert archive / North Carolina / Flash Flood Warnings in 2017

Flash Flood Warning 21, NWS Blacksburg, VA

October 23, 2017Alleghany County, Ashe County, Watauga County, North Carolina

NWS Blacksburg, VA issued this flash flood warning at Oct 23, 2017, 2:46 PM EDT for Alleghany County, Ashe County, Watauga County, North Carolina. It was in force for 6 hr. 5 reports 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
Oct 23, 2017, 2:46 PM EDT (18:46 UTC)
Expired
Oct 23, 2017, 8:45 PM EDT
In force
6 hr
Issued by
NWS Blacksburg, VA
Area
Storm-based polygon
Flood severity
None

Counties Alleghany County, NC, Ashe County, NC, Watauga County, NC

The radar

The Roanoke radar (KFCX), 125 km from the middle of the area, began a volume at 18:49 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

TimeReportWhereRemark
Oct 23, 5:00 PM EDTFLASH FLOOD1 Ne Boone, NCEXCESSIVE RUNOFF FROM A THUNDERSTORM CAUSED A STREAM TO OVERFLOW ITS BANKS,FLOODING PORTIONS OF EAST KING STREET IN BOONE, NC. A CAR WAS SHOWN STRANDED IN THAT INTERSECTION.
Oct 23, 5:00 PM EDTFLASH FLOODJefferson, NCLOTS OF REPORTS OF ROADS FLOODED IN JEFFERSON AND WEST JEFFERSON BETWEEN 5 AND 7PM.
Oct 23, 5:10 PM EDTFLASH FLOOD1 Ne Boone, NCPERSISTENT RAINS FROM THUNDERSTORMS CAUSED A CREEK TO SIGNIFICANTLY FLOOD A PARKING LOT NEAR THE NEW MARKET CENTER IN BOONE, NC. 3 TO 6 INCHES OF FLOWING WATER VISIBLE IN VIDEO FOOTAGE SHARED ON SOCIAL MEDIA.
Oct 23, 5:50 PM EDTFLOOD5 N Blowing Rock, NCPERSISTENT RAINFALL IN AN AREA OF POOR DRAINAGE HAS CAUSED SEVERAL FEET OF WATER TO POND IN THE BOONE WALMART PARKING LOT. SEVERAL CARS ARE PICTURED STRANDED.
Oct 23, 6:40 PM EDTFLASH FLOOD4 S Grassy Creek, NCROADS FLOODED IN CRUMPLER AREA.

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

The nearest sounding before it

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 6.8 hours before the alert went out and 137 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, Greensboro/Hi Pt, NC at 12:00Z on 2017-10-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 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, Greensboro/Hi Pt, NC at 12:00Z on 2017-10-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 202 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
597 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
202 m²/s²
0-3 km storm-relative helicity
259 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

099 
WGUS51 KRNK 231846
FFWRNK
NCC005-009-189-240045-
/O.NEW.KRNK.FF.W.0021.171023T1846Z-171024T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service BLACKSBURG VA
246 PM EDT MON OCT 23 2017

The National Weather Service in BLACKSBURG has issued a

* Flash Flood Warning for...
  Alleghany County in northwestern North Carolina...
  Watauga County in northwestern North Carolina...
  Central Ashe County in northwestern North Carolina...

* Until 845 PM EDT Monday

* At 244 PM EDT, Doppler radar indicated heavy rainfall about to 
  move back into the region from the south. Rain gauges have 
  indicated as much as three to four inches of rain has already 
  fallen since this morning. Flash flooding is expected to begin 
  shortly.

* Some locations that will experience flooding include...
  Boone...
  Sparta...
  Jefferson...
  West Jefferson...
  and Blowing Rock.

Additional rainfall amounts of two to three inches are possible in 
the warned area and much of it will come in a period of less than 
two hours.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses as
well as other drainage areas and low lying spots.

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 3630 8191 3632 8172 3652 8139 3657 8104
      3656 8090 3645 8098 3642 8095 3638 8098
      3638 8103 3643 8108 3643 8117 3637 8124
      3637 8136 3630 8137 3625 8148 3614 8150
      3612 8154 3611 8180 3621 8190 3623 8191

$$

SK
3 follow-up statements
374 
WGUS71 KRNK 232051
FFSRNK

Flash Flood Statement
National Weather Service BLACKSBURG VA
451 PM EDT MON OCT 23 2017

NCC005-009-189-240045-
/O.CON.KRNK.FF.W.0021.000000T0000Z-171024T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Alleghany NC-Watauga NC-Ashe NC-
451 PM EDT MON OCT 23 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 845 PM EDT FOR 
ALLEGHANY...WATAUGA AND CENTRAL ASHE COUNTIES IN NORTHWESTERN NORTH
CAROLINA...

At 446 PM EDT, Doppler radar and automated rain gauges indicated 
that heavy rain was continuing to fall over the area. In some 
locations such as around Foscoe and Blowing Rock, as much as six 
inches of rain has fallen. Reports are starting to comer in across 
the county of mud slides, road closures, and may trees down due to 
wet ground and gusty winds. An additional inch or so of rain is 
still possible before the rain finally tapers off around 6pm EDT. 
Flash flooding is expected to continue through this evening.

Some locations that will experience flooding include...
Boone...
Sparta...
Jefferson...
West Jefferson...
and Blowing Rock.

Flood waters are also moving down the Watauga River and it has 
exceeded flood stage at Sugar Grove and is still rising rapidly.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This is a dangerous situation! Turn around, don't drown when 
encountering flooded roads. Most flood deaths occur in vehicles.

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses 
as well as other drainage areas and low lying spots. Additional 
mudslides are likely as well.

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 3630 8191 3632 8172 3652 8139 3657 8104
      3656 8090 3645 8098 3642 8095 3638 8098
      3638 8103 3643 8108 3643 8117 3637 8124
      3637 8136 3630 8137 3625 8148 3614 8150
      3612 8154 3611 8180 3621 8190 3623 8191

$$

SK
542 
WGUS71 KRNK 232232
FFSRNK

Flash Flood Statement
National Weather Service BLACKSBURG VA
632 PM EDT MON OCT 23 2017

NCC005-009-189-240045-
/O.CON.KRNK.FF.W.0021.000000T0000Z-171024T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Alleghany NC-Watauga NC-Ashe NC-
632 PM EDT MON OCT 23 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 845 PM EDT FOR 
ALLEGHANY...WATAUGA AND CENTRAL ASHE COUNTIES IN NORTHWESTERN NORTH
CAROLINA...

At 627 PM EDT, Doppler radar and automated rain gauges indicated 
that heavy rain had moved out of the area, however runoff was. still 
resulting in flash flooding in Boone as well as rapid river rises 
along the Watauga and Middle Fork of the New River.

While rain has ended across the warned area, mud slides near steep 
terrain are still possible. A mud slide can consist of rock, mud, 
vegetation and other loose materials.

Some locations that will experience flooding include...
Boone...
Sparta...
Jefferson...
West Jefferson...
and Blowing Rock.

Flood waters are moving down the Watauga River and at Sugar Grove it 
is approaching moderate flood stage at 630 pm EDT. The Middle Fork 
of the New Rover at Boone was over flood stage of 12 ft at 6pm and 
still rising.

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.

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses as
well as other drainage areas and low lying spots.

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 3630 8191 3632 8172 3652 8139 3657 8104
      3656 8090 3645 8098 3642 8095 3638 8098
      3638 8103 3643 8108 3643 8117 3637 8124
      3637 8136 3630 8137 3625 8148 3614 8150
      3612 8154 3611 8180 3621 8190 3623 8191

$$

SK
474 
WGUS71 KRNK 240036
FFSRNK

Flash Flood Statement
National Weather Service BLACKSBURG VA
836 PM EDT MON OCT 23 2017

NCC005-009-189-240044-
/O.CAN.KRNK.FF.W.0021.000000T0000Z-171024T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Alleghany NC-Watauga NC-Ashe NC-
836 PM EDT MON OCT 23 2017

...THE FLASH FLOOD WARNING FOR 
ALLEGHANY...WATAUGA AND CENTRAL ASHE COUNTIES IN NORTHWESTERN NORTH
CAROLINA IS CANCELLED...

The heavy rain has ended. However, runoff from early rain may still 
cause some flooding mainly in Watauga County and a new Areal Flood 
Warning has been issued for that County, which replaces this Flash 
Flood Warning. In Ashe and Alleghany Counties, any lingering 
flooding is minor and does not pose a significant threat. Please 
continue to heed any remaining road closures however.

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 3630 8191 3632 8172 3652 8139 3657 8104
      3656 8090 3645 8098 3642 8095 3638 8098
      3638 8103 3643 8108 3643 8117 3637 8124
      3637 8136 3630 8137 3625 8148 3614 8150
      3612 8154 3611 8180 3621 8190 3623 8191

$$

SK

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 23, 10:46 AM EDTFlash Flood WatchRNKAlleghany, Ashe, Watauga9 hr
Oct 23, 5:00 PM EDTTornado WarningRNKAshe, Wilkes30 min
Oct 23, 5:23 PM EDTSevere Thunderstorm WarningRNKSurry, Wilkes, Yadkin67 min
Oct 23, 5:26 PM EDTTornado WarningRNKAlleghany, Ashe, Surry, Wilkes34 min
Oct 23, 5:47 PM EDTSevere Thunderstorm WarningRNKStokes, Surry, Yadkin58 min
Oct 23, 5:55 PM EDTTornado WarningRNKAlleghany, Surry35 min
Oct 23, 6:46 PM EDTSevere Thunderstorm WarningRNKRockingham, Stokes59 min
Oct 23, 7:16 PM EDTTornado WarningRNKCaswell, Rockingham29 min
Oct 23, 7:50 PM EDTSpecial Weather StatementRNKCaswell55 min

Nearby

Flash Flood Warnings in North Carolina, 2017Every flash flood warning in 2017

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.