Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 122, NWS Salt Lake City, UT

August 19, 2021Garfield County, Kane County, San Juan County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 19, 2021, 2:03 AM MDT for Garfield County, Kane County, San Juan County, Utah. It was in force for 6 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 19, 2021, 2:03 AM MDT (08:03 UTC)
Expired
Aug 19, 2021, 8:00 AM MDT
In force
6 hr
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

Counties Garfield County, UT, Kane County, UT, San Juan County, UT

The radar

The Cedar City radar (KICX), 149 km from the middle of the area, began a volume at 08:04 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

Flgstf/Belemont, AZ (KFGZ), launched 00:00Z, 8.1 hours before the alert went out and 268 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, Flgstf/Belemont, AZ at 00:00Z on 2021-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 605 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Flgstf/Belemont, AZ at 00:00Z on 2021-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 109 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
605 J/kg
Mixed-layer CIN
-17 J/kg
Mixed-layer LCL
745 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
109 m²/s²
0-3 km storm-relative helicity
108 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.8

Open this sounding in Storm Lab

The text

As transmitted.

658 
WGUS55 KSLC 190803
FFWSLC
UTC017-025-037-191400-
/O.NEW.KSLC.FF.W.0122.210819T0803Z-210819T1400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
203 AM MDT Thu Aug 19 2021

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  San Juan County in southeastern Utah...
  South Central Garfield County in southern Utah...
  Northeastern Kane County in southern Utah...

* Until 800 AM MDT.

* At 203 AM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.75 and 1.25 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...
  Escalante and Boulder.

This includes the following streams and drainages...
  Harris Wash, Wide Hollow, Death Hollow, Sand Creek, Pine Creek, 
  Boulder Creek, The Gulch, and the Escalante River.

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.

Remain alert for flooding even in locations not receiving rain. Dry 
washes, streams, and rivers can become raging killer currents in a 
matter of minutes, even from distant rainfall.

&&

LAT...LON 3763 11123 3761 11136 3776 11178 3787 11165
      3795 11142 3788 11125 3778 11127 3769 11120
      3760 11110 3752 11099 3737 11092 3729 11085
      3728 11084 3727 11087 3735 11096 3746 11103

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

$$

LC
2 follow-up statements
950 
WGUS75 KSLC 190925
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
325 AM MDT Thu Aug 19 2021

UTC017-025-037-191400-
/O.CON.KSLC.FF.W.0122.000000T0000Z-210819T1400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Garfield UT-Kane UT-San Juan UT-
325 AM MDT Thu Aug 19 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 8 AM MDT THIS MORNING 
FOR SAN JUAN, SOUTH CENTRAL GARFIELD AND NORTHEASTERN KANE 
COUNTIES...

At 325 AM MDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 0.75 and 1.25 inches of rain 
have fallen. In addition, the river gage on the Escalante River near 
Escalante showed a significant rise. Flash flooding is already 
occurring.

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...
  Escalante and Boulder.

This includes the following streams and drainages...
  Harris Wash, Wide Hollow, Death Hollow, Sand Creek, Pine Creek, 
  Boulder Creek, The Gulch, and the Escalante River.

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.

Remain alert for flooding even in locations not receiving rain. Dry 
washes, streams, and rivers can become raging killer currents in a 
matter of minutes, even from distant rainfall.

&&

LAT...LON 3763 11123 3761 11136 3776 11178 3787 11165
      3795 11142 3788 11125 3778 11127 3769 11120
      3760 11110 3752 11099 3737 11092 3729 11085
      3728 11084 3727 11087 3735 11096 3746 11103

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

$$

LC
271 
WGUS75 KSLC 191352
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
752 AM MDT Thu Aug 19 2021

UTC017-025-037-191402-
/O.EXP.KSLC.FF.W.0122.000000T0000Z-210819T1400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Garfield UT-Kane UT-San Juan UT-
752 AM MDT Thu Aug 19 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 8 AM MDT THIS MORNING FOR SAN 
JUAN, SOUTH CENTRAL GARFIELD AND NORTHEASTERN KANE COUNTIES...

The heavy rain has ended. All area normally dry washes, streams and 
rivers will continue to run high today.

LAT...LON 3763 11123 3761 11136 3776 11178 3787 11165
      3795 11142 3788 11125 3778 11127 3769 11120
      3760 11110 3752 11099 3737 11092 3729 11085
      3728 11084 3727 11087 3735 11096 3746 11103

$$

CRK

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 18, 7:43 PM MDTFlash Flood Warning Considerable damage threatSLCKane4 hr
Aug 18, 8:01 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield3 hr
Aug 18, 8:46 PM MDTSpecial Weather StatementSLCIron44 min
Aug 18, 9:39 PM MDTFlash Flood Warning Considerable damage threatSLCIron, Washington3 hr
Aug 18, 9:48 PM MDTAreal Flood AdvisorySLCIron5 min
Aug 18, 9:53 PM MDTFlash Flood Warning Considerable damage threatSLCIron3 hr
Aug 18, 10:07 PM MDTFlash Flood Warning Considerable damage threatSLCIron3 hr
Aug 18, 11:11 PM MDTFlash Flood Warning Considerable damage threatSLCKane, Washington5 hr
Aug 19, 1:43 AM MDTFlash Flood Warning Considerable damage threatSLCGarfield, Wayne3 hr
Aug 19, 2:31 AM MDTFlash Flood Warning Considerable damage threatSLCKane3 hr
Aug 19, 3:50 AM MDTSpecial Weather StatementSLC25 min
Aug 19, 9:39 AM MDTSpecial Weather StatementSLCKane36 min
Aug 19, 10:16 AM MDTRiver Flood WarningSLCDuchesne4 hr
Aug 19, 10:54 AM MDTSpecial Weather StatementSLCJuab51 min
Aug 19, 11:15 AM MDTAreal Flood AdvisorySLCMillard2 hr
Aug 19, 11:42 AM MDTSpecial Weather StatementSLCSanpete48 min
Aug 19, 12:29 PM MDTSpecial Weather StatementSLCSanpete46 min
Aug 19, 12:49 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield, Wayne3 hr
Aug 19, 1:04 PM MDTSpecial Weather StatementSLCUtah56 min
Aug 19, 1:25 PM MDTSpecial Weather StatementSLCCarbon50 min
Aug 19, 2:12 PM MDTSpecial Weather StatementSLCCarbon, Duchesne63 min
Aug 19, 2:59 PM MDTSpecial Weather StatementSLCDuchesne61 min

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.