Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 13, NWS Salt Lake City, UT

July 16, 2021Kane County, Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 16, 2021, 12:39 AM MDT for Kane County, Washington 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 16, 2021, 12:39 AM MDT (06:39 UTC)
Expired: Jul 16, 2021, 3:45 AM MDT
In force: 3 hr
Issued by: NWS Salt Lake City, UT
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Kane County, UT, Washington County, UT

The radar

The Cedar City radar (KICX), 33 km from the middle of the area, began a volume at 06:40 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 00:00Z, 6.7 hours before the alert went out and 245 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: 688 J/kg
Mixed-layer CIN: -18 J/kg
Mixed-layer LCL: 3158 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: 9 m²/s²
0-3 km storm-relative helicity: 16 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

845 
WGUS55 KSLC 160639
FFWSLC
UTC025-053-160945-
/O.NEW.KSLC.FF.W.0013.210716T0639Z-210716T0945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
1239 AM MDT Fri Jul 16 2021

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  Western Kane County in southern Utah...
  East Central Washington County in southwestern Utah...

* Until 345 AM MDT.

* At 1239 AM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. 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...
  Zion National Park, Springdale, Rockville and Kolob Canyon.

This warning includes large portions of Zion National Park including 
Behunin Canyon, the Narrows, Echo Canyon, Keyhole, Spry and Pine 
Slot Canyons, the Subway and the Kolob Canyons area of the park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3748 11327 3747 11306 3737 11290 3728 11290
      3725 11290 3721 11290 3715 11303 3729 11308
      3735 11314 3739 11324

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

$$

CRK

2 follow-up statements

238 
WGUS75 KSLC 160807
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
207 AM MDT Fri Jul 16 2021

UTC025-053-160945-
/O.CON.KSLC.FF.W.0013.000000T0000Z-210716T0945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kane UT-Washington UT-
207 AM MDT Fri Jul 16 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 345 AM MDT EARLY THIS 
MORNING FOR WESTERN KANE AND EAST CENTRAL WASHINGTON COUNTIES...

At 207 AM MDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Flash flooding is already occurring.

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

SOURCE...Radar.

IMPACT...Life threatening flash flooding of streams, normally dry
         washes, slot canyons and area roads.

Some locations that will experience flash flooding include...
  Zion National Park, Springdale, Rockville and Kolob Canyon.

This warning includes large portions of Zion National Park including 
Behunin Canyon, the Narrows, Echo Canyon, Keyhole, Spry and Pine 
Slot Canyons, the Subway and the Kolob Canyons area of the park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

Flooding is occurring or is imminent. It is important to know where 
you are relative to streams, rivers, or creeks which can become 
killers in heavy rains. Campers and hikers should avoid streams or 
creeks.

&&

LAT...LON 3748 11327 3747 11306 3737 11290 3728 11290
      3725 11290 3721 11290 3715 11303 3729 11308
      3735 11314 3739 11324

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

$$

CRK

039 
WGUS75 KSLC 160936
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
336 AM MDT Fri Jul 16 2021

UTC025-053-160946-
/O.EXP.KSLC.FF.W.0013.000000T0000Z-210716T0945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kane UT-Washington UT-
336 AM MDT Fri Jul 16 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 345 AM MDT EARLY THIS MORNING 
FOR WESTERN KANE AND EAST CENTRAL WASHINGTON COUNTIES...

The heavy rain has ended. Elevated flows will continue across slot 
canyons, normally dry washes and streams in the area through at 
least mid-morning.

A Flash Flood Watch remains in effect until 600 AM MDT for a portion 
of southwest Utah.

LAT...LON 3748 11327 3747 11306 3737 11290 3728 11290
      3725 11290 3721 11290 3715 11303 3729 11308
      3735 11314 3739 11324

$$

CRK

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 15, 6:35 PM MDT	Special Weather Statement	SLC	Salt Lake	40 min
Jul 15, 7:08 PM MDT	Severe Thunderstorm Warning	SLC	Iron	52 min
Jul 15, 8:39 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Beaver, Iron	3 hr
Jul 16, 1:05 AM MDT	Flash Flood Warning Considerable damage threat	SLC	Kane, Washington	3 hr
Jul 16, 1:09 AM MDT	Areal Flood Advisory	SLC	Washington	3 hr
Jul 16, 1:07 PM MDT	Special Weather Statement	SLC	Kane	38 min
Jul 16, 1:27 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Kane	3 hr
Jul 16, 1:58 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Garfield, Kane	3 hr
Jul 16, 3:20 PM MDT	Special Weather Statement	SLC		40 min
Jul 16, 3:47 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Garfield, Kane	3 hr
Jul 16, 4:46 PM MDT	Special Weather Statement	SLC	Millard	44 min
Jul 16, 5:04 PM MDT	Severe Thunderstorm Warning	SLC	Millard	56 min

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.