Alert archive / Utah / Flash Flood Warnings in 2017

Flash Flood Warning 16, NWS Salt Lake City, UT

July 24, 2017Garfield County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 24, 2017, 5:00 PM MDT for Garfield County, Utah. It was in force for 4 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 24, 2017, 5:00 PM MDT (23:00 UTC)
Expired
Jul 24, 2017, 9:00 PM MDT
In force
4 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), 120 km from the middle of the area, began a volume at 22:59 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

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 11.0 hours before the alert went out and 278 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 2017-07-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 8 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 2017-07-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 62 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
8 J/kg
Mixed-layer CIN
-42 J/kg
Mixed-layer LCL
973 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
62 m²/s²
0-3 km storm-relative helicity
37 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

236 
WGUS55 KSLC 242300
FFWSLC
UTC017-250300-
/O.NEW.KSLC.FF.W.0016.170724T2300Z-170725T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
500 PM MDT MON JUL 24 2017

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  South central Garfield County in southern Utah...Specifically for 
  the normally dry washes around Escalante including Birch Creek 
  and North Creek, and the upper portions of the Escalante River

* Until 900 PM MDT
    
* At 457 PM MDT, Doppler radar indicated a thunderstorms producing 
  heavy rain over the upper Escalante River basin. One to two inches 
  of rain has already fallen, and potential exists for an additional 
  inch of rainfall through early evening. Flash flooding is expected 
  to begin shortly.

* Some locations that will experience flooding include...
  Escalante.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3781 11153 3769 11118 3763 11122 3765 11129
      3760 11148 3770 11164 3771 11184 3784 11184

$$

GM
2 follow-up statements
038 
WGUS75 KSLC 250125
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
725 PM MDT MON JUL 24 2017

UTC017-250300-
/O.CON.KSLC.FF.W.0016.000000T0000Z-170725T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Garfield UT-
725 PM MDT MON JUL 24 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 900 PM MDT FOR
SOUTH CENTRAL GARFIELD COUNTY...

At 721 PM MDT, Flash flooding is occurring in the headwater areas of 
the Escalante River.  Reports of flooding include Birch and Upper 
Valley Creeks in the headwaters of the Escalante River Drainage, 
just northwest of the town of Escalante.

Rainfall over the area is moderate to light with the possibility to 
encounter additional rainfall during the nighttime hours. 

The flood is now flowing through the system and is expected to 
attenuate farther down the mainstem Escalante River later tonight.
 
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.

&&

LAT...LON 3781 11153 3769 11118 3763 11122 3765 11129
      3760 11148 3770 11164 3771 11184 3784 11184

$$

McInerney
087 
WGUS75 KSLC 250246
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
846 PM MDT MON JUL 24 2017

UTC017-250300-
/O.CON.KSLC.FF.W.0016.000000T0000Z-170725T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Garfield UT-
846 PM MDT MON JUL 24 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 900 PM MDT FOR
SOUTH CENTRAL GARFIELD COUNTY...

At 843 PM MDT, Flash flooding occurred in the Birch Creek and to a 
lesser extent Upper Valley Creek.  Both tributaries flow into the 
Escalante River near the town of Escalante.  The Escalante rose to 
near 800 cubic feet per second (CFS) as a result.

The danger of imminent flash flooding has passed.

Rainfall in the area has decreased and is expected to produce 
moderate widespread amounts throughout the nighttime hours. As such, 
it is best if you avoid low lying areas in and around the Escalante 
upper drainage, and the Escalante River mainstem tonight.

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.

&&

LAT...LON 3781 11153 3769 11118 3763 11122 3765 11129
      3760 11148 3770 11164 3771 11184 3784 11184

$$

McInerney

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 24, 3:30 AM MDTFlash Flood WatchSLC42 hr
Jul 24, 1:26 PM MDTFlash Flood WarningSLCGarfield, Iron3 hr
Jul 24, 2:09 PM MDTFlash Flood WarningSLCGarfield, Iron3 hr
Jul 24, 2:33 PM MDTAreal Flood AdvisorySLCIron117 min
Jul 24, 5:38 PM MDTFlash Flood WarningSLCGarfield, Kane3 hr

Nearby

Flash Flood Warnings in Utah, 2017Every flash flood warning in 2017

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.