Alert archive / Nevada / Flash Flood Warnings in 2021

Flash Flood Warning 5, NWS Reno, NV

July 30, 2021Douglas County, Nevada

NWS Reno, NV issued this flash flood warning at Jul 30, 2021, 6:25 PM PDT for Douglas County, Nevada. It was in force for 107 min. 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 30, 2021, 6:25 PM PDT (01:25 UTC)
Expired: Jul 30, 2021, 8:12 PM PDT
In force: 107 min
Issued by: NWS Reno, NV
Area: Storm-based polygon
Flood severity: None

County Douglas County, NV

The radar

The Reno radar (KRGX), 99 km from the middle of the area, began a volume at 01:27 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

Reno, NV (KREV), launched 00:00Z, 1.4 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: 3 J/kg
Mixed-layer CIN: -64 J/kg
Mixed-layer LCL: 2942 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: -1 m²/s²
0-3 km storm-relative helicity: 78 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

309 
WGUS55 KREV 310125
FFWREV
NVC005-310330-
/O.NEW.KREV.FF.W.0005.210731T0125Z-210731T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Reno NV
625 PM PDT Fri Jul 30 2021

The National Weather Service in Reno has issued a

* Flash Flood Warning for...
  Douglas County in western Nevada...

* Until 830 PM PDT.

* At 625 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Flash flooding is ongoing or 
  expected to begin shortly.

Excessive rainfall over the burn scar will result in potential 
debris flow moving through the Numbers and Monarch Burn Areas. The 
debris flow can consist of rock, mud, vegetation and other loose 
materials.

  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...
  Mount Siegel.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move away from recently burned areas. Life-threatening flooding of 
creeks, roads, and normally dry stream beds is likely. The heavy 
rains will likely trigger rockslides, mudslides and debris flows in 
steep terrain, especially in and around these areas.

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

&&

LAT...LON 3890 11962 3891 11959 3891 11956 3890 11951
      3889 11950 3886 11950 3884 11951 3882 11951
      3882 11953 3882 11955 3883 11958 3884 11959
      3886 11962 3888 11963 3889 11963 3890 11963

FLASH FLOOD...RADAR INDICATED

$$

EW

1 follow-up statement

068 
WGUS75 KREV 310312
FFSREV

Flash Flood Statement
National Weather Service Reno NV
812 PM PDT Fri Jul 30 2021

NVC005-310322-
/O.CAN.KREV.FF.W.0005.000000T0000Z-210731T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Douglas NV-
812 PM PDT Fri Jul 30 2021

...FLASH FLOOD WARNING IS CANCELLED FOR DOUGLAS COUNTY...

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 1100 PM PDT for portions 
of east central California and western Nevada.

LAT...LON 3890 11962 3891 11959 3891 11956 3890 11951
      3889 11950 3886 11950 3884 11951 3882 11951
      3882 11953 3882 11955 3883 11958 3884 11959
      3886 11962 3888 11963 3889 11963 3890 11963

$$

EW

The office that day

Everything else NWS Reno, NV issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 30, 5:02 PM PDT	Special Weather Statement	REV		88 min
Jul 30, 5:10 PM PDT	Flash Flood Warning	REV	Douglas	110 min
Jul 30, 5:34 PM PDT	Special Weather Statement	REV	Churchill, Douglas, Lyon, Mineral, Pershing, Storey and 1 more	86 min
Jul 30, 6:27 PM PDT	Areal Flood Advisory	REV	Douglas, Lyon	6 hr
Jul 31, 4:40 PM PDT	Special Weather Statement	REV	Mineral	50 min

Nearby

Flash Flood Warnings in Nevada, 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.