Alert archive / Utah / Flash Flood Warnings in 2018

Flash Flood Warning 39, NWS Salt Lake City, UT

July 19, 2018Iron County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 19, 2018, 3:51 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, 2018, 3:51 PM MDT (21:51 UTC)
Expired: Jul 19, 2018, 6:45 PM MDT
In force: 3 hr
Issued by: NWS Salt Lake City, UT
Area: Storm-based polygon
Flood severity: None

County Iron County, UT

The radar

The Cedar City radar (KICX), 12 km from the middle of the area, began a volume at 21:52 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, 9.9 hours before the alert went out and 269 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: 1086 J/kg
Mixed-layer CIN: -186 J/kg
Mixed-layer LCL: 2450 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: -24 m²/s²
0-3 km storm-relative helicity: -7 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.0

Open this sounding in Storm Lab

The text

As transmitted.

259 
WGUS55 KSLC 192151
FFWSLC
UTC021-200045-
/O.NEW.KSLC.FF.W.0039.180719T2151Z-180720T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
351 PM MDT THU JUL 19 2018

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  South central Iron County in southern Utah...

* Until 645 PM MDT
    
* At 348 PM MDT, Intense rainfall has produced a debris flow over 
  SR14 leading from Cedar Breaks NM to Cedar City.  It is inferred 
  that the amount of intense rainfall produced rocks and debris onto 
  the road.  

* Radar rainfall estimates are currently up to 1.5 inches of rain 
  and the continuing.

* Please avoid SR14 for the foreseeable future.

* Some locations that will experience flooding include...
  Cedar City.

LAT...LON 3765 11289 3759 11292 3765 11308 3769 11305
      3768 11298

$$

McInerney

2 follow-up statements

180 
WGUS75 KSLC 192323
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
523 PM MDT THU JUL 19 2018

UTC021-200045-
/O.CON.KSLC.FF.W.0039.000000T0000Z-180720T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Iron UT-
523 PM MDT THU JUL 19 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 645 PM MDT FOR
SOUTH CENTRAL IRON COUNTY...

At 520 PM MDT, Thunderstorm activity has ceased in the Coal Creek 
Canyon.  However, due to earlier thunderstorms and resultant debris 
onto the SR14, the road remains closed and potentially hazardous to 
additional debris from above.

Please avoid this area for the foreseeable future.


LAT...LON 3765 11289 3759 11292 3765 11308 3769 11305
      3768 11298

$$

McInerney

274 
WGUS75 KSLC 200037
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
637 PM MDT THU JUL 19 2018

UTC021-200045-
/O.EXP.KSLC.FF.W.0039.000000T0000Z-180720T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Iron UT-
637 PM MDT THU JUL 19 2018

...THE FLASH FLOOD WARNING FOR SOUTH CENTRAL IRON COUNTY WILL EXPIRE
AT 645 PM MDT...

Thunderstorm activity over Coal Creek Canyon feeding into Cedar City 
has slowed and flash flooding is no longer occurring.  However due 
to earlier flooding, residual high water and road debris may remain 
in the area.

Please be aware of hazardous conditions through the evening hours.

LAT...LON 3765 11289 3759 11292 3765 11308 3769 11305
      3768 11298

$$

McInerney

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 18, 6:23 PM MDT	Special Weather Statement	SLC	Iron	37 min
Jul 18, 9:21 PM MDT	Areal Flood Advisory	SLC	Kane	114 min
Jul 18, 10:46 PM MDT	Flash Flood Warning	SLC	Kane	3 hr
Jul 19, 2:44 AM MDT	Flash Flood Watch	SLC		20 hr
Jul 19, 2:19 PM MDT	Flash Flood Warning	SLC	Garfield, Kane, San Juan	8 hr
Jul 19, 5:33 PM MDT	Flash Flood Warning	SLC	Kane, Washington	3 hr
Jul 19, 5:40 PM MDT	Flash Flood Warning	SLC	Washington	3 hr

Nearby

Flash Flood Warnings in Utah, 2018 Every flash flood warning in 2018

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.