Alert archive / Utah / Flash Flood Warnings in 2017

Flash Flood Warning 21, NWS Salt Lake City, UT

July 25, 2017Garfield County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 25, 2017, 2:54 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 25, 2017, 2:54 PM MDT (20:54 UTC)
Expired: Jul 25, 2017, 6:45 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), 135 km from the middle of the area, began a volume at 20:55 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

Grand Junction, CO (KGJT), launched 12:00Z, 8.9 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-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: 1053 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 16 m²/s²
0-3 km storm-relative helicity: 137 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

465 
WGUS55 KSLC 252054
FFWSLC
UTC017-260045-
/O.NEW.KSLC.FF.W.0021.170725T2054Z-170726T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
254 PM MDT TUE JUL 25 2017

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  Central Garfield County in southern Utah...

* Until 645 PM MDT
    
* At 248 PM MDT, Doppler radar indicated a line of thunderstorms 
  moving across a wide swath of the Grand Staircase Escalante 
  Monument stretching from Escalante along SR12 to Boulder. this 
  amount and extent of rainfall is expected to produce flash 
  flooding across a wide area.  

* Radar   rainfall estimates over this area include 1 inch of 
  rainfall in approximately 30 minutes.

* This area is highly flash flood prone and contains a great 
  magnitude of slot canyons and dry washes.

* If you are traveling through this area, please be vigilant to 
  flash flooding.  Take steps to ensure for your safety.


LAT...LON 3800 11123 3778 11107 3761 11117 3768 11137
      3784 11161 3800 11164 3811 11159 3814 11147

$$

McInerney

2 follow-up statements

624 
WGUS75 KSLC 252251
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
451 PM MDT TUE JUL 25 2017

UTC017-260045-
/O.CON.KSLC.FF.W.0021.000000T0000Z-170726T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Garfield UT-
451 PM MDT TUE JUL 25 2017

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

At 447 PM MDT, Thunderstorm activity has diminished over the 
headwaters of the Escalante Drainage. However, due to the amount and 
intensity of the rainfall that had fallen earlier, flash flooding is 
anticipated to be coursing through the drainage.

Widespread rainfall over over 1 inch fell in about a 30 minute 
window.  This rain fell over an extremely flash flood area including 
Calf, Boulder, Durfey, Steep,Sweetwater, and a few others.

If you plan on traveling through these areas, please be aware of the 
flash flood threat.

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 3800 11123 3778 11107 3761 11117 3768 11137
      3784 11161 3800 11164 3811 11159 3814 11147

$$

McInerney

851 
WGUS75 KSLC 260038
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
638 PM MDT TUE JUL 25 2017

UTC017-260046-
/O.EXP.KSLC.FF.W.0021.000000T0000Z-170726T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Garfield UT-
638 PM MDT TUE JUL 25 2017

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

Thunderstorm activity in the Escalante River headwater areas has 
diminished.  Additionally, enough time has lapsed since the heavier 
precipitation hours ago to allow the flash flood to attenuate.

However, please be aware that remaining high water may remain 
throughout the evening and nighttime hours.

The threat of flash flooding in this area is no longer a threat.

LAT...LON 3800 11123 3778 11107 3761 11117 3768 11137
      3784 11161 3800 11164 3811 11159 3814 11147

$$

McInerney

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 24, 9:35 PM MDT	Flash Flood Warning	SLC	Washington	3 hr
Jul 25, 6:36 AM MDT	Areal Flood Advisory	SLC	Washington	3 hr
Jul 25, 9:43 AM MDT	Areal Flood Advisory	SLC	Washington	2 hr
Jul 25, 12:51 PM MDT	Flash Flood Warning	SLC	Kane	4 hr
Jul 25, 1:34 PM MDT	Flash Flood Warning	SLC	Kane	4 hr

Nearby

Flash Flood Warnings in Utah, 2017 Every 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.