Alert archive / Utah / Flash Flood Warnings in 2018

Flash Flood Warning 49, NWS Salt Lake City, UT

August 2, 2018Garfield County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 2, 2018, 1:00 PM MDT for Garfield County, Utah. It was in force for 3 hr. 2 reports 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
Aug 2, 2018, 1:00 PM MDT (19:00 UTC)
Expired
Aug 2, 2018, 4:00 PM MDT
In force
3 hr
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Flood severity
None

County Garfield County, UT

The radar

The Cedar City radar (KICX), 55 km from the middle of the area, began a volume at 19:01 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

TimeReportWhereRemark
Aug 2, 1:15 PM MDTFLASH FLOOD5 Ene Hillsdale, UTMUD FROM A FLASH FLOOD IS COVERING HALF OF THE PARKING LOT AT THE RED CANYON VISITOR CENTER.
Aug 2, 1:35 PM MDTFLASH FLOOD5 Ene Hillsdale, UTSTATE ROUTE 12 CLOSED DUE TO MUD COVERING A FEW SECTIONS OF ROADWAY.

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, 7.0 hours before the alert went out and 285 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 12:00Z on 2018-08-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 46 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 12:00Z on 2018-08-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 40 square meters per square second.1939Sfc1 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
46 J/kg
Mixed-layer CIN
-155 J/kg
Mixed-layer LCL
2011 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
40 m²/s²
0-3 km storm-relative helicity
33 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

897 
WGUS55 KSLC 021900
FFWSLC
UTC017-022200-
/O.NEW.KSLC.FF.W.0049.180802T1900Z-180802T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
100 PM MDT THU AUG 2 2018

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  West central Garfield County in southern Utah...
  Specifically for Red Canyon

* Until 400 PM MDT
    
* At 1257 PM MDT, Doppler radar indicated a thunderstorm producing 
  heavy rain over Red Canyon. Radar estimates of .50 inches of rain 
  have fallen in the last 20 minutes. Additional heavy rainfall is 
  expected over the next hour. Flash flooding is expected to begin 
  shortly.

* Stay out of normally dry washes in the Red Canyon area. Campers in 
  the area should move to higher ground immediately.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3782 11221 3768 11225 3769 11237 3779 11234

$$

GM
3 follow-up statements
667 
WGUS75 KSLC 021923
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
123 PM MDT THU AUG 2 2018

UTC017-022200-
/O.CON.KSLC.FF.W.0049.000000T0000Z-180802T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Garfield UT-
123 PM MDT THU AUG 2 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 400 PM MDT FOR
WEST CENTRAL GARFIELD COUNTY...
Specifically for Red Canyon

At 118 PM MDT, trained weather spotters at the USFS Red Canyon 
Visitor Center reported flash flooding in Red Canyon, with a mud 
slide covering half of the parking lot. 1 to 1.25 inches of rain has 
fallen in the last 45 min, and additional heavy rain is expected 
over the next hour.

If in the Red Canyon area, move to higher ground immediately! Flash 
flooding and mud slides will continue to occur through mid 
afternoon. 


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to higher ground now. Act quickly to protect your life.

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 3782 11221 3768 11225 3769 11237 3779 11234

$$

GM
236 
WGUS75 KSLC 022036
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
236 PM MDT THU AUG 2 2018

UTC017-022200-
/O.CON.KSLC.FF.W.0049.000000T0000Z-180802T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Garfield UT-
236 PM MDT THU AUG 2 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 400 PM MDT FOR
WEST CENTRAL GARFIELD COUNTY...

At 228 PM MDT, USFS employees at the Red Canyon Visitor Center have 
indicated that flash flooding continues in all major washes in the 
canyon. UDOT has reported that SR 12 remains closed through Red 
Canyon, as multiple mud slides have crossed the road. 2 cars were 
trapped between slides, but all occupants were able to escape with 
no injuries.

Radar estimates of 1-2 inches of rain fell within a 1 hour period 
earlier this afternoon, but rainfall has since ended. Ongoing flash 
flooding within the main channels will only gradually recede through 
4 pm MDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 3782 11221 3768 11225 3769 11237 3779 11234

$$

GM
448 
WGUS75 KSLC 022159
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
359 PM MDT THU AUG 2 2018

UTC017-022203-
/O.EXP.KSLC.FF.W.0049.000000T0000Z-180802T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Garfield UT-
359 PM MDT THU AUG 2 2018

...THE FLASH FLOOD WARNING FOR WEST CENTRAL GARFIELD COUNTY WILL
EXPIRE AT 400 PM MDT...

Flood waters continue to recede within the Red Canyon area, and road 
crews have made progress cleaning up remaining mud slide debris on 
SR 12. Additional flooding is no longer expected to pose a threat. 
Please continue to heed any remaining road closures.

LAT...LON 3782 11221 3768 11225 3769 11237 3779 11234

$$

GM

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 2, 5:46 PM MDTSevere Thunderstorm WarningSLCTooele44 min

Nearby

Flash Flood Warnings in Utah, 2018Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.