Alert archive / Wyoming / Flash Flood Warnings in 2018

Flash Flood Warning 13, NWS Riverton, WY

June 17, 2018Fremont County, Wyoming

NWS Riverton, WY issued this flash flood warning at Jun 17, 2018, 11:14 PM MDT for Fremont County, Wyoming. It was in force for 8 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: Jun 17, 2018, 11:14 PM MDT (05:14 UTC)
Expired: Jun 18, 2018, 7:00 AM MDT
In force: 8 hr
Issued by: NWS Riverton, WY
Area: Storm-based polygon
Flood severity: None

County Fremont County, WY

The radar

The Riverton/Lander radar (KRIW), 45 km from the middle of the area, began a volume at 05:13 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

Riverton, WY (KRIW), launched 00:00Z, 5.2 hours before the alert went out and 51 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: 694 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 55 m²/s²
0-3 km storm-relative helicity: 158 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

376 
WGUS55 KRIW 180514
FFWRIW
WYC013-181300-
/O.NEW.KRIW.FF.W.0013.180618T0514Z-180618T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Riverton WY
1114 PM MDT SUN JUN 17 2018

The National Weather Service in Riverton has issued a

* Flash Flood Warning for...
  Central Fremont County in central Wyoming...

* Until 700 AM MDT Monday.

* At 1112 PM MDT, Doppler radar indicated heavy rain across the 
  warned area. Two to three inches of rain have fallen in the Wind 
  River Mountains over a three hour period. Flash flooding is 
  expected to begin shortly.

* Some locations that will experience flooding include...
  Areas along Sage Creek and its drainages, and along the North Fork 
  Little Wind River. Outlying areas near Fort Washakie and Ethete 
  along these creeks will be impacted by the flood waters.

Additional rainfall amounts of one-half to one inch are possible in 
the warned area through 4 AM MDT Monday.

Flood waters are likely moving down North Fork Sage Creek, South 
Fork Sage Creek, Sage Creek, and North Fork Little Wind River. Both 
Sage Creek and North Fork Little Wind River cross underneath US 
Highway 287. Sage Creek eventually drains into the Little Wind River 
upstream of Ethete and crosses under Blue Sky Highway north of 
Ethete. Sage Creek Road northwest of Fort Washakie may also be 
impacted by flood waters.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles. Be especially cautious at night when it is 
harder to recognize the dangers of flooding.

&&

LAT...LON 4304 10873 4300 10884 4301 10897 4301 10909
      4296 10914 4293 10931 4303 10934 4312 10932
      4316 10910 4313 10895 4305 10884

$$

CNJ

4 follow-up statements

393 
WGUS75 KRIW 180623
FFSRIW

Flash Flood Statement
National Weather Service Riverton WY
1223 AM MDT MON JUN 18 2018

WYC013-181300-
/O.CON.KRIW.FF.W.0013.000000T0000Z-180618T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Fremont-
1223 AM MDT MON JUN 18 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 700 AM MDT MONDAY
FOR CENTRAL FREMONT COUNTY...

At 1222 AM MDT, Doppler radar indicated an estimated two to three 
inches of rain fell in a three hour period late Sunday evening. 
Hourly totals of one-quarter to one-half inch were common in the 
headwaters of Sage Creek and North Fork Little Wind River. Flash 
flooding is expected to begin shortly or is already ongoing.

Additional rainfall amounts of one-half to one inch are possible in 
the warned area through 4 AM MDT Monday.

The watersheds most likely to experience flooding early Monday 
morning are those of Sage Creek and North Fork Little Wind River. 
This includes North Fork Sage Creek, South Fork Sage Creek, Sage 
Creek, and North Fork Little Wind River.

Both Sage Creek and North Fork Little Wind River pass underneath US 
Highway 287 between Fort Washakie north toward Winkleman Dome. Sage 
Creek eventually drains into the Little Wind River upstream of 
Ethete and passes under Blue Sky Highway north of Ethete. Sage Creek 
Road northwest of Fort Washakie and low lying areas along Washakie 
Park Road west of Fort Washakie may both be impacted by flood waters.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles. Be especially cautious at night when it is 
harder to recognize the dangers of flooding.

&&

LAT...LON 4304 10873 4300 10884 4301 10897 4301 10909
      4296 10914 4293 10931 4303 10934 4312 10932
      4316 10910 4313 10895 4305 10884

$$

CNJ

628 
WGUS75 KRIW 180854
FFSRIW

Flash Flood Statement
National Weather Service Riverton WY
254 AM MDT MON JUN 18 2018

WYC013-181300-
/O.CON.KRIW.FF.W.0013.000000T0000Z-180618T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Fremont-
254 AM MDT MON JUN 18 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 700 AM MDT FOR
CENTRAL FREMONT COUNTY...

At 250 AM MDT, Doppler radar indicated heavy rain across the warned
area. Up to three inches of rain have already fallen. Flash flooding
is likely occurring.

Additional rainfall amounts of one half to one inch are possible in 
the warned area through 5 AM MDT.

Some locations that will experience flooding include...Areas 
along Sage Creek and its drainages, and along the North Fork Little 
Wind River. Outlying areas near Fort Washakie and Ethete along these 
creeks will be impacted by the flood waters.

Flood waters are likely moving down North Fork Sage Creek, South 
Fork Sage Creek, Sage Creek, and North Fork Little Wind River. Both 
Sage Creek and North Fork Little Wind River cross underneath US 
Highway 287. Sage Creek eventually drains into the Little Wind River 
upstream of Ethete and crosses under Blue Sky Highway north of 
Ethete. Sage Creek Road northwest of Fort Washakie may also be 
impacted by flood waters.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

Please report flooding to your local law enforcement agency when you
can do so safely.

&&

LAT...LON 4304 10873 4300 10884 4301 10897 4301 10909
      4296 10914 4293 10931 4303 10934 4312 10932
      4316 10910 4313 10895 4305 10884

$$

13

088 
WGUS75 KRIW 181129
FFSRIW

Flash Flood Statement
National Weather Service Riverton WY
529 AM MDT MON JUN 18 2018

WYC013-181300-
/O.CON.KRIW.FF.W.0013.000000T0000Z-180618T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Fremont-
529 AM MDT MON JUN 18 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 700 AM MDT FOR
CENTRAL FREMONT COUNTY...

At 525 AM MDT, Doppler radar indicated continued showers and 
isolated thunderstorms moving across the warned area. Up to three 
inches of rain have already fallen earlier in the night. Flash 
flooding is has likely occurred overnight and may still be 
occurring.

Some locations that will experience flooding include...
Fort Washakie and Ethete. 

Additional rainfall amounts of one quarter to one half inch are 
possible in the warned area by sunrise. More rain may fall across 
the area later today and tonight and even through Tuesday so be alert
not only this morning but through at least Tuesday.

Some locations that will experience flooding include...Areas 
along Sage Creek and its drainages, and along the North Fork Little 
Wind River. Outlying areas near Fort Washakie and Ethete along these 
creeks will be impacted by the flood waters.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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.

Please report flooding to your local law enforcement agency when you
can do so safely.

&&

LAT...LON 4304 10873 4300 10884 4301 10897 4301 10909
      4296 10914 4293 10931 4303 10934 4312 10932
      4316 10910 4313 10895 4305 10884

$$

13

008 
WGUS75 KRIW 181254
FFSRIW

Flash Flood Statement
National Weather Service Riverton WY
654 AM MDT MON JUN 18 2018

WYC013-181301-
/O.EXP.KRIW.FF.W.0013.000000T0000Z-180618T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Fremont-
654 AM MDT MON JUN 18 2018

...THE FLASH FLOOD WARNING FOR CENTRAL FREMONT COUNTY WILL EXPIRE AT
700 AM MDT...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. However, off and on showers and thunderstorms are still in 
the forecast today through Tuesday. Additional flooding is possible 
around the area again today and possibly into Tuesday.

LAT...LON 4304 10873 4300 10884 4301 10897 4301 10909
      4296 10914 4293 10931 4303 10934 4312 10932
      4316 10910 4313 10895 4305 10884

$$

13

The office that day

Everything else NWS Riverton, WY issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 17, 6:44 PM MDT	Special Weather Statement	RIW	Sublette	31 min
Jun 17, 7:52 PM MDT	Special Weather Statement	RIW		23 min
Jun 18, 5:55 AM MDT	Areal Flood Advisory	RIW	Fremont	10 hr
Jun 18, 12:08 PM MDT	Special Weather Statement	RIW		37 min
Jun 18, 1:33 PM MDT	Areal Flood Advisory	RIW	Teton	24 hr
Jun 18, 2:02 PM MDT	Special Weather Statement	RIW	Natrona	43 min
Jun 18, 2:21 PM MDT	Special Weather Statement	RIW	Fremont	39 min
Jun 18, 2:40 PM MDT	Areal Flood Advisory	RIW	Big Horn, Park	24 hr
Jun 18, 3:17 PM MDT	Special Weather Statement	RIW	Big Horn	28 min
Jun 18, 3:39 PM MDT	Special Weather Statement	RIW	Big Horn	36 min
Jun 18, 3:46 PM MDT	Special Weather Statement	RIW	Washakie	29 min
Jun 18, 4:06 PM MDT	Areal Flood Warning	RIW	Fremont	49 hr
Jun 18, 4:14 PM MDT	Special Weather Statement	RIW	Big Horn	31 min
Jun 18, 4:41 PM MDT	Special Weather Statement	RIW		34 min
Jun 18, 5:06 PM MDT	Special Weather Statement	RIW	Big Horn	39 min

Nearby

Flash Flood Warnings in Wyoming, 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.