Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 214, NWS Flagstaff, AZ

August 18, 2021Gila County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Aug 18, 2021, 7:59 PM MST for Gila County, Arizona. 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: Aug 18, 2021, 7:59 PM MST (02:59 UTC)
Expired: Aug 19, 2021, 12:00 AM MST
In force: 4 hr
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Gila County, AZ

The radar

The Flagstaff radar (KFSX), 66 km from the middle of the area, began a volume at 03:01 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.

The nearest sounding before it

Phoenix, AZ (KPSR), launched 00:00Z, 3.0 hours before the alert went out and 87 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: 510 J/kg
Mixed-layer CIN: -174 J/kg
Mixed-layer LCL: 1692 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 157 m²/s²
0-3 km storm-relative helicity: 230 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.7

Open this sounding in Storm Lab

The text

As transmitted.

016 
WGUS55 KFGZ 190259
FFWFGZ
AZC007-190600-
/O.NEW.KFGZ.FF.W.0214.210819T0259Z-210819T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
759 PM MST Wed Aug 18 2021

The National Weather Service in Flagstaff has issued a

* Flash Flood Warning for...
  Gila County in east central Arizona...

* Until 1100 PM MST.

* At 757 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Flash flooding is likely 
  ongoing across Tonto Creek. A 2ft rise was registered on a gauge 
  along Tonto Creek.

  HAZARD...Life-threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar.

  IMPACT...Life-threatening flash flooding of low-water
           crossings, creeks, normally dry washes and roads.

* Some locations that will experience flash flooding include...
  mainly rural areas of Gila County

This includes the following highways...
	State Route 188 between mile markers 267 and 268...and
	between mile markers 270 and 272.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Flooding of washes and creeks will occur, some dirt roads will 
become muddy and impassable. Paved roads and underpasses could 
become flooded as well.

In hilly or mountainous terrain, there are many low water crossings 
which will become dangerous in heavy rain. Do not attempt to cross 
flooded roads. Find an alternate route.

Remain alert for flooding even in locations not receiving rain. 
Normally dry washes, slot canyons and creeks can become raging 
killer currents in a matter of minutes, even from distant rainfall.

&&

LAT...LON 3393 11132 3395 11132 3398 11133 3402 11130
      3403 11129 3405 11129 3405 11127 3403 11127
      3396 11130 3391 11129

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

ET

5 follow-up statements

345 
WGUS75 KFGZ 190316
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
816 PM MST Wed Aug 18 2021

AZC007-190600-
/O.CON.KFGZ.FF.W.0214.000000T0000Z-210819T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Gila AZ-
816 PM MST Wed Aug 18 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 11 PM MST THIS 
EVENING FOR GILA COUNTY...

At 814 PM MST, heavy rain has ended across the warned area. Flash 
flooding is ongoing or expected to begin shortly. Tonto Creek has 
risen 2.3 feet and will continue to rise.

HAZARD...Life-threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar.

IMPACT...Life-threatening flash flooding of low-water crossings,
         creeks, normally dry washes and roads.

Some locations that will experience flash flooding include...
  mainly rural areas of Gila County

This includes the following highways...
	State Route 188 between mile markers 267 and 268...and
	between mile markers 270 and 272.

This includes the following streams and drainages...
  Slate Creek, Hardt Creek, Rye Creek, Gun Creek, Tonto Creek and 
  Cottonwood Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Flooding of washes and creeks will occur, some dirt roads will 
become muddy and impassable. Paved roads and underpasses could 
become flooded as well.

In hilly or mountainous terrain, there are many low water crossings 
which will become dangerous in heavy rain. Do not attempt to cross 
flooded roads. Find an alternate route.

Remain alert for flooding even in locations not receiving rain. 
Normally dry washes, slot canyons and creeks can become raging 
killer currents in a matter of minutes, even from distant rainfall.

&&

LAT...LON 3393 11132 3395 11132 3398 11133 3402 11130
      3403 11129 3405 11129 3405 11127 3403 11127
      3396 11130 3391 11129

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

ET

228 
WGUS75 KFGZ 190335
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
835 PM MST Wed Aug 18 2021

AZC007-190600-
/O.CON.KFGZ.FF.W.0214.000000T0000Z-210819T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Gila AZ-
835 PM MST Wed Aug 18 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 11 PM MST THIS 
EVENING FOR GILA COUNTY...

At 835 PM MST, heavy rain had ended across the warned area. Flash 
flooding is likely ongoing across Tonto Creek. A 2ft rise was 
registered on a gauge along Tonto Creek.

HAZARD...Life-threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar.

IMPACT...Life-threatening flash flooding of low-water crossings,
         creeks, normally dry washes and roads.

Some locations that will experience flash flooding include...
  mainly rural areas of Gila County

This includes the following highways...
	State Route 188 between mile markers 267 and 268...and
	between mile markers 270 and 272.

This includes the following streams and drainages...
  Slate Creek, Hardt Creek, Rye Creek, Gun Creek, Tonto Creek and 
  Cottonwood Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Flooding of washes and creeks will occur, some dirt roads will 
become muddy and impassable. Paved roads and underpasses could 
become flooded as well.

In hilly or mountainous terrain, there are many low water crossings 
which will become dangerous in heavy rain. Do not attempt to cross 
flooded roads. Find an alternate route.

Remain alert for flooding even in locations not receiving rain. 
Normally dry washes, slot canyons and creeks can become raging 
killer currents in a matter of minutes, even from distant rainfall.

&&

LAT...LON 3393 11132 3395 11132 3398 11133 3402 11130
      3403 11129 3405 11129 3405 11127 3403 11127
      3396 11130 3391 11129 3392 11130

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

ET

664 
WGUS75 KFGZ 190336
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
836 PM MST Wed Aug 18 2021

AZC007-190600-
/O.CON.KFGZ.FF.W.0214.000000T0000Z-210819T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Gila AZ-
836 PM MST Wed Aug 18 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 11 PM MST THIS 
EVENING FOR GILA COUNTY...

At 836 PM MST, heavy rain had ended across the warned area. Flash 
flooding is likely ongoing across Tonto Creek. A 2ft rise was 
registered on a gauge along Tonto Creek.

HAZARD...Life-threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar.

IMPACT...Life-threatening flash flooding of low-water crossings,
         creeks, normally dry washes and roads.

Some locations that will experience flash flooding include...
  mainly rural areas of Gila County

This includes the following highways...
	State Route 188 between mile markers 267 and 268...and
	between mile markers 270 and 272.

This includes the following streams and drainages...
  Slate Creek, Hardt Creek, Rye Creek, Gun Creek, Tonto Creek and 
  Cottonwood Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Flooding of washes and creeks will occur, some dirt roads will 
become muddy and impassable. Paved roads and underpasses could 
become flooded as well.

In hilly or mountainous terrain, there are many low water crossings 
which will become dangerous in heavy rain. Do not attempt to cross 
flooded roads. Find an alternate route.

Remain alert for flooding even in locations not receiving rain. 
Normally dry washes, slot canyons and creeks can become raging 
killer currents in a matter of minutes, even from distant rainfall.

&&

LAT...LON 3393 11132 3395 11132 3398 11133 3402 11130
      3403 11129 3405 11129 3405 11127 3403 11127
      3396 11130 3392 11129 3392 11130

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

ET

976 
WGUS55 KFGZ 190554
FFWFGZ
AZC007-190700-
/O.EXT.KFGZ.FF.W.0214.000000T0000Z-210819T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
1054 PM MST Wed Aug 18 2021

The National Weather Service in Flagstaff has extended the

* Flash Flood Warning for...
  Gila County in east central Arizona...

* Until midnight MST.

* At 1052 PM MST, gauges along Tonto Creek indicated that Tonto 
  Creek had crested but continued to show elevated flow. Flash 
  flooding is ongoing.

  HAZARD...Life-threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar.

  IMPACT...Life-threatening flash flooding of low-water
           crossings, creeks, normally dry washes and roads.

* Some locations that will experience flash flooding include...
  mainly rural areas of Gila County

This includes the following highways...
	State Route 188 between mile markers 267 and 268...and
	between mile markers 270 and 272.

This includes the following streams and drainages...
  Slate Creek, Hardt Creek, Rye Creek, Gun Creek, Tonto Creek and 
  Cottonwood Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Flooding of washes and creeks will occur, some dirt roads will 
become muddy and impassable. Paved roads and underpasses could 
become flooded as well.

In hilly or mountainous terrain, there are many low water crossings 
which will become dangerous in heavy rain. Do not attempt to cross 
flooded roads. Find an alternate route.

Remain alert for flooding even in locations not receiving rain. 
Normally dry washes, slot canyons and creeks can become raging 
killer currents in a matter of minutes, even from distant rainfall.

&&

LAT...LON 3393 11132 3395 11132 3398 11133 3402 11130
      3403 11129 3405 11129 3405 11127 3403 11127
      3396 11130 3392 11129 3392 11130

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

ET

403 
WGUS75 KFGZ 190654
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
1154 PM MST Wed Aug 18 2021

AZC007-190704-
/O.EXP.KFGZ.FF.W.0214.000000T0000Z-210819T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Gila AZ-
1154 PM MST Wed Aug 18 2021

...FLASH FLOOD WARNING WILL EXPIRE AT MIDNIGHT MST TONIGHT FOR GILA 
COUNTY...

Tonto Creek will continue to gradually recede overnight. Please 
continue to heed remaining road closures.

LAT...LON 3393 11132 3395 11132 3398 11133 3402 11130
      3403 11129 3405 11129 3405 11127 3403 11127
      3396 11130 3392 11129 3392 11130

$$

TPS

The office that day

Everything else NWS Flagstaff, AZ issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 18, 5:13 PM MST	Flash Flood Warning	FGZ	Yavapai	3 hr
Aug 18, 5:17 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Yavapai	4 hr
Aug 18, 5:31 PM MST	Special Weather Statement	FGZ	Yavapai	29 min
Aug 18, 5:43 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	23 min
Aug 18, 8:08 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	6 hr
Aug 18, 10:41 PM MST	Areal Flood Warning	FGZ	Gila, Yavapai	10 hr
Aug 18, 11:56 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	8 hr

Nearby

Flash Flood Warnings in Arizona, 2021 Every flash flood warning in 2021

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.