Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 20, NWS Salt Lake City, UT

July 19, 2021Iron County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 19, 2021, 3:04 PM MDT for Iron County, Utah. 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 19, 2021, 3:04 PM MDT (21:04 UTC)
Expired
Jul 19, 2021, 6:00 PM MDT
In force
3 hr
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Iron County, UT

The radar

The Cedar City radar (KICX), 47 km from the middle of the area, began a volume at 21:03 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

Las Vegas, NV (KVEF), launched 12:00Z, 9.1 hours before the alert went out and 234 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, Las Vegas, NV at 12:00Z on 2021-07-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 127 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, Las Vegas, NV at 12:00Z on 2021-07-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 17 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
127 J/kg
Mixed-layer CIN
-232 J/kg
Mixed-layer LCL
1964 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
17 m²/s²
0-3 km storm-relative helicity
68 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

796 
WGUS55 KSLC 192104
FFWSLC
UTC021-200000-
/O.NEW.KSLC.FF.W.0020.210719T2104Z-210720T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
304 PM MDT Mon Jul 19 2021

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  Southwestern Iron County in southern Utah...

* Until 600 PM MDT.

* At 304 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 2 inches of 
  rain have fallen. 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...
  Portions of SR-56 between Cedar City and Old Irontown

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3758 11341 3759 11343 3761 11345 3762 11345
      3763 11342 3762 11341 3762 11335 3760 11335
      3757 11336 3758 11337

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

$$

SW
2 follow-up statements
921 
WGUS75 KSLC 192228
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
428 PM MDT Mon Jul 19 2021

UTC021-200000-
/O.CON.KSLC.FF.W.0020.000000T0000Z-210720T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Iron UT-
428 PM MDT Mon Jul 19 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 6 PM MDT THIS EVENING 
FOR SOUTHWESTERN IRON COUNTY...

At 428 PM MDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 2.5 and 3.5 inches of rain have 
fallen. Flash flooding is ongoing or expected to begin shortly 
within the warned area. Flash flooding has been reported nearby.

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...
  mainly rural areas of Southwestern Iron County

This includes the following highways...
	Utah Route 56 between mile markers 40 and 44.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3758 11341 3759 11343 3761 11345 3762 11345
      3763 11342 3762 11341 3762 11335 3760 11335
      3757 11336 3758 11337

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

$$

SW
823 
WGUS75 KSLC 200002
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
602 PM MDT Mon Jul 19 2021

UTC021-200012-
/O.EXP.KSLC.FF.W.0020.000000T0000Z-210720T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Iron UT-
602 PM MDT Mon Jul 19 2021

...FLASH FLOOD WARNING HAS EXPIRED FOR SOUTHWESTERN IRON COUNTY...

The heavy rain has decreased across the warned area. Flooding is no 
longer expected to pose a threat. Additional moderate to heavy 
rainfall is anticipated over the next 1 to 2 hours. Please continue 
to heed remaining road closures.

A Flash Flood Watch remains in effect until 1200 AM MDT for portions 
of central Utah, southern Utah and southwest Utah.

LAT...LON 3758 11341 3759 11343 3761 11345 3762 11345
      3763 11342 3762 11341 3762 11335 3760 11335
      3757 11336 3758 11337

$$

SW

The office that day

Everything else NWS Salt Lake City, UT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 18, 7:02 PM MDTSpecial Weather StatementSLCTooele43 min
Jul 18, 7:54 PM MDTSpecial Weather StatementSLCTooele51 min
Jul 19, 4:32 AM MDTFlash Flood WatchSLCBeaver, Carbon, Duchesne, Emery, Garfield, Iron and 12 more19 hr
Jul 19, 1:44 PM MDTFlash Flood Warning Considerable damage threatSLCKane, Washington5 hr
Jul 19, 2:34 PM MDTFlash Flood Warning Considerable damage threatSLCIron, Washington3 hr
Jul 19, 2:45 PM MDTAreal Flood AdvisorySLCIron3 hr
Jul 19, 2:53 PM MDTSpecial Weather StatementSLCIron52 min
Jul 19, 3:22 PM MDTSevere Thunderstorm WarningSLCIron38 min
Jul 19, 3:46 PM MDTSpecial Weather StatementSLCUtah44 min
Jul 19, 4:54 PM MDTSpecial Weather StatementSLCDavis, Salt Lake36 min
Jul 19, 5:57 PM MDTFlash Flood Warning Considerable damage threatSLCIron, Washington3 hr

Nearby

Flash Flood Warnings in Utah, 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.