Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 33, NWS Salt Lake City, UT

July 22, 2021Garfield County, Kane County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 22, 2021, 3:46 PM MDT for Garfield County, Kane County, Utah. It was in force for 7 hr. 1 report 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: Jul 22, 2021, 3:46 PM MDT (21:46 UTC)
Expired: Jul 22, 2021, 10:37 PM MDT
In force: 7 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

The radar

The Cedar City radar (KICX), 79 km from the middle of the area, began a volume at 21:49 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

Time	Report	Where	Remark
Jul 22, 8:15 PM MDT	FLASH FLOOD	14 Wnw Big Water, UT	PARIA RIVER NEAR KANAB RIVER GAGE HAD A 3 FOOT RISE WITH PEAK FLOWS OF 1800 CFS.

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

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 9.8 hours before the alert went out and 237 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: 196 J/kg
Mixed-layer CIN: -125 J/kg
Mixed-layer LCL: 1415 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 11 m²/s²
0-3 km storm-relative helicity: 54 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

901 
WGUS55 KSLC 222146
FFWSLC
UTC017-025-230445-
/O.NEW.KSLC.FF.W.0033.210722T2146Z-210723T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
346 PM MDT Thu Jul 22 2021

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  Southern Garfield County in southern Utah...
  Central Kane County in southern Utah...

* Until 1045 PM MDT Thursday.

* At 346 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the upper Paria River Basin area, including Bull 
  Valley Gorge, Sheep Creek, and Dunham Slot Canyon. Between 1 and 2 
  inches of rain have fallen across the upper basin. Additionally, a 
  flood wave is tracking south from Tropic within the Paria River, 
  so multiple flash flood waves are likely as they continue 
  downstream to the Arizona border through the middle of the night 
  tonight. Additional thunderstorm activity will likely occur within 
  the warned area periodically through this evening.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding.

* Some locations that will experience flash flooding include...
  The Paria River basin and its tributaries.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3755 11219 3755 11214 3758 11209 3755 11205
      3746 11207 3738 11204 3739 11199 3739 11194
      3726 11189 3700 11179 3700 11183 3700 11191
      3719 11196 3731 11204 3736 11210 3746 11219

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

$$

GM

1 follow-up statement

496 
WGUS75 KSLC 230437
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
1037 PM MDT Thu Jul 22 2021

UTC017-025-230447-
/O.CAN.KSLC.FF.W.0033.000000T0000Z-210723T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Garfield UT-Kane UT-
1037 PM MDT Thu Jul 22 2021

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHERN GARFIELD AND 
CENTRAL KANE COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat.

LAT...LON 3755 11219 3755 11214 3758 11209 3755 11205
      3746 11207 3738 11204 3739 11199 3739 11194
      3726 11189 3700 11179 3700 11183 3700 11191
      3719 11196 3731 11204 3736 11210 3746 11219

$$

WFO SLC

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 21, 8:41 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Kane	6 hr
Jul 22, 2:43 AM MDT	Flash Flood Watch	SLC	Emery, Garfield, Kane, Sevier, Washington, Wayne	20 hr
Jul 22, 11:16 AM MDT	Special Weather Statement	SLC	Piute	29 min
Jul 22, 11:41 AM MDT	Special Weather Statement	SLC		49 min
Jul 22, 11:54 AM MDT	Flood Watch	SLC	Beaver, Garfield, Iron, Kane, Piute, Washington and 1 more	11 hr
Jul 22, 1:02 PM MDT	Special Weather Statement	SLC	Iron	43 min
Jul 22, 1:13 PM MDT	Special Weather Statement	SLC	Garfield	32 min
Jul 22, 1:18 PM MDT	Areal Flood Advisory	SLC	Iron	117 min
Jul 22, 1:20 PM MDT	Severe Thunderstorm Warning	SLC	Garfield	25 min
Jul 22, 1:45 PM MDT	Special Weather Statement	SLC	Kane	45 min
Jul 22, 2:00 PM MDT	Special Weather Statement	SLC	Beaver	30 min
Jul 22, 2:13 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Garfield, Kane	3 hr
Jul 22, 2:13 PM MDT	Severe Thunderstorm Warning	SLC	Beaver	32 min
Jul 22, 2:34 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Kane, Washington	3 hr
Jul 22, 2:42 PM MDT	Areal Flood Advisory	SLC	Beaver	2 hr
Jul 22, 2:58 PM MDT	Severe Thunderstorm Warning	SLC	Washington	32 min
Jul 22, 3:08 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Garfield, Wayne	3 hr
Jul 22, 3:14 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Garfield, Kane	5 hr
Jul 22, 3:14 PM MDT	Special Weather Statement	SLC	Washington	46 min
Jul 22, 3:30 PM MDT	Severe Thunderstorm Warning	SLC	Garfield
Jul 22, 4:02 PM MDT	Severe Thunderstorm Warning	SLC	Iron	28 min
Jul 22, 4:15 PM MDT	Special Weather Statement	SLC	Box Elder	30 min
Jul 22, 4:28 PM MDT	Severe Thunderstorm Warning	SLC	Iron	32 min
Jul 22, 4:48 PM MDT	Special Weather Statement	SLC	Washington	27 min
Jul 22, 5:51 PM MDT	Special Weather Statement	SLC		39 min
Jul 22, 5:58 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Utah	3 hr

Nearby

Flash Flood Warnings in Utah, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.