Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 136, NWS Salt Lake City, UT

October 5, 2021Kane County, Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Oct 5, 2021, 4:01 PM MDT for Kane County, Washington County, Utah. It was in force for 4 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: Oct 5, 2021, 4:01 PM MDT (22:01 UTC)
Expired: Oct 5, 2021, 8:00 PM MDT
In force: 4 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), 42 km from the middle of the area, began a volume at 22:01 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
Oct 5, 4:01 PM MDT	FLASH FLOOD	3 Ssw Zion Np, UT	NPS REPORTS PINE CREEK IS EXPERIENCING A FLASH FLOOD.

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, 10.0 hours before the alert went out and 244 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 986 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 121 m²/s²
0-3 km storm-relative helicity: 140 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

310 
WGUS55 KSLC 052201
FFWSLC
UTC025-053-060200-
/O.NEW.KSLC.FF.W.0136.211005T2201Z-211006T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
401 PM MDT Tue Oct 5 2021

The National Weather Service in Salt Lake City has issued a

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

* Until 800 PM MDT.

* At 401 PM 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 slot canyons,
           creeks and streams, urban areas, highways, streets and
           underpasses.

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

This includes the following streams and drainages...
  Pine Creek, Lower Clear Creek, Spry Canyon, Keyhole Canyon. These 
  storms are expected to move north up Zion Canyon producing 
  additional flash flooding.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 3714 11297 3715 11302 3737 11301 3737 11285
      3714 11285

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

$$

GM

2 follow-up statements

526 
WGUS75 KSLC 060003
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
603 PM MDT Tue Oct 5 2021

UTC025-053-060200-
/O.CON.KSLC.FF.W.0136.000000T0000Z-211006T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kane UT-Washington UT-
603 PM MDT Tue Oct 5 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 8 PM MDT THIS EVENING 
FOR WEST CENTRAL KANE AND EAST CENTRAL WASHINGTON COUNTIES...

At 603 PM MDT, local law enforcement reported flash flooding and 
heavy rainfall. Flash flooding is already occurring.

HAZARD...Life threatening flash flooding.

SOURCE...Law enforcement reported.

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

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

This includes the following streams and drainages...
  Pine Creek, Lower Clear Creek, Spry Canyon, Keyhole Canyon. These 
  storms are expected to move north up Zion Canyon producing 
  additional flash flooding.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 3714 11297 3715 11302 3737 11301 3737 11285
      3714 11285

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

CRK

709 
WGUS75 KSLC 060152
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
752 PM MDT Tue Oct 5 2021

UTC025-053-060202-
/O.EXP.KSLC.FF.W.0136.000000T0000Z-211006T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kane UT-Washington UT-
752 PM MDT Tue Oct 5 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 8 PM MDT THIS EVENING FOR WEST 
CENTRAL KANE AND EAST CENTRAL WASHINGTON COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Normally dry washes, slot canyons and area streams will 
continue to run high through the evening.

LAT...LON 3714 11297 3715 11302 3737 11301 3737 11285
      3714 11285

$$

CRK

The office that day

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

Issued	Product	Office	Counties	Lasted
Oct 5, 3:07 PM MDT	Special Weather Statement	SLC	Washington	38 min
Oct 5, 3:40 PM MDT	Special Weather Statement	SLC	Washington	50 min
Oct 5, 4:03 PM MDT	Special Weather Statement	SLC	Kane	42 min
Oct 5, 4:43 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Kane	4 hr
Oct 5, 5:42 PM MDT	Special Weather Statement	SLC	Kane	48 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.