Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 228, NWS Flagstaff, AZ

September 18, 2021Yavapai County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Sep 18, 2021, 5:52 PM MST for Yavapai County, Arizona. It was in force for 4 hr. 3 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: Sep 18, 2021, 5:52 PM MST (00:52 UTC)
Expired: Sep 18, 2021, 10:00 PM MST
In force: 4 hr
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Yavapai County, AZ

The radar

The Flagstaff radar (KFSX), 117 km from the middle of the area, began a volume at 00:54 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

Time	Report	Where	Remark
Sep 18, 6:32 PM MST	FLASH FLOOD	Granite Creek Park In P, AZ	PUBLIC VIDEO ON TWITTER SHOWED ONGOING FLASH FLOODING OF GRANITE CREEK IN GRANITE CREEK PARK ABOUT A MILE NORTH OF PRESCOTT COURTHOUSE.
Sep 18, 7:00 PM MST	FLASH FLOOD	1 Nne Prescott Courthou, AZ	USGS GAGE GCRA3 (09502960) ROSE APPROXIMATELY 4.15 FEET BETWEEN 4:45 PM AND 615 PM MST. CREEK HEIGHT THEN BEGAN TO DECREASE AFTER 7 PM MST.
Sep 18, 7:00 PM MST	FLASH FLOOD	2 Ne Prescott Courthous, AZ	USGS GAGE GRCA3 (09503000) ROSE APPROXIMATELY 4.5 FEET BETWEEN 5 PM AND 7 PM MST. THE CREEK HEIGHT THEN BEGAN TO FALL AFTER 7.

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 00:00Z, 0.9 hours before the alert went out and 89 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: 60 J/kg
Mixed-layer CIN: -37 J/kg
Mixed-layer LCL: 1034 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 70 m²/s²
0-3 km storm-relative helicity: 121 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

917 
WGUS55 KFGZ 190052
FFWFGZ
AZC025-190400-
/O.NEW.KFGZ.FF.W.0228.210919T0052Z-210919T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
552 PM MST Sat Sep 18 2021

The National Weather Service in Flagstaff has issued a

* Flash Flood Warning for...
  Yavapai County near the Prescott area in west central Arizona...

* Until 900 PM MST.

* At 550 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 1.5 inches of 
  rain have fallen. Additional rainfall amounts of 0.5 to 1.5 inches 
  are possible in the Prescott area. Flash flooding is ongoing or 
  expected to begin shortly.

  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...
  Chino Valley, Prescott, Oak Knoll Village, and White Spar 
  Campground.

This includes the following highways...
	State Route 69 between mile markers 295 and 296.
	State Route 89 between mile markers 309 and 333.
	State Route 89A between mile markers 318 and 319.

This includes the following creeks, washes and rivers...
  Verde River, Copper Basin Wash, Granite Creek, Mint Wash, Little 
  Chino Valley, Bottleneck Wash, Spence Creek, Willow Creek, Butte 
  Creek, Bannon Creek, and Miller Creek.

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 3451 11256 3455 11255 3465 11251 3474 11247
      3485 11245 3485 11239 3470 11237 3451 11244

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

$$

TM

5 follow-up statements

059 
WGUS75 KFGZ 190135
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
635 PM MST Sat Sep 18 2021

AZC025-190400-
/O.CON.KFGZ.FF.W.0228.000000T0000Z-210919T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
635 PM MST Sat Sep 18 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 9 PM MST THIS EVENING 
FOR THE GREATER PRESCOTT AREA IN YAVAPAI COUNTY...

At 633 PM MST, Doppler radar indicated thunderstorms producing 
moderate to heavy rain across the warned area. Between 1 and 1.75 
inches of rain have fallen. Additional rainfall amounts of 0.25 to 
0.5 inches are possible in the Prescott area over the next hour. 
Flash flooding is ongoing or expected to begin shortly.

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...
  Chino Valley, Prescott, Oak Knoll Village, and White Spar 
  Campground.

This includes the following highways...
	State Route 69 between mile markers 295 and 296.
	State Route 89 between mile markers 309 and 332.
	State Route 89A between mile markers 318 and 319.

This includes the following creeks, washes and rivers...
  Verde River, Copper Basin Wash, Granite Creek, Mint Wash, Little 
  Chino Valley, Bottleneck Wash, Spence Creek, Willow Creek, Butte 
  Creek, Bannon Creek, and Miller Creek.

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 3451 11256 3455 11255 3465 11251 3474 11247
      3485 11245 3485 11239 3470 11237 3451 11244

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

$$

NL

075 
WGUS75 KFGZ 190152
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
652 PM MST Sat Sep 18 2021

AZC025-190400-
/O.CON.KFGZ.FF.W.0228.000000T0000Z-210919T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
652 PM MST Sat Sep 18 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 9 PM MST THIS EVENING 
FOR THE GREATER PRESCOTT AREA IN YAVAPAI COUNTY...

At 648 PM MST, the public reported flash flooding in Granite Creek 
Park. Between 1 and 1.75 inches of rain have fallen. Additional 
rainfall amounts up to 0.10 inches are possible in the Prescott area 
over the next half hour. Flash flooding is already occurring along 
Granite Creek.

HAZARD...Life-threatening flash flooding. Heavy rain producing
         flash flooding.

SOURCE...Public reported.

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

Some locations that will experience flash flooding include...
  Chino Valley, Prescott, Oak Knoll Village, and White Spar 
  Campground.

This includes the following highways...
	State Route 69 between mile markers 295 and 296.
	State Route 89 between mile markers 309 and 332.
	State Route 89A between mile markers 318 and 319.

This includes the following creeks, washes and rivers...
  Verde River, Copper Basin Wash, Granite Creek, Mint Wash, Little 
  Chino Valley, Bottleneck Wash, Spence Creek, Willow Creek, Butte 
  Creek, Bannon Creek and Miller Creek.

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 3451 11256 3455 11255 3465 11251 3474 11247
      3485 11245 3485 11239 3470 11237 3451 11244

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

NL

446 
WGUS75 KFGZ 190234
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
734 PM MST Sat Sep 18 2021

AZC025-190400-
/O.CON.KFGZ.FF.W.0228.000000T0000Z-210919T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
734 PM MST Sat Sep 18 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 9 PM MST THIS EVENING 
FOR THE GREATER PRESCOTT AREA IN YAVAPAI COUNTY...

At 734 PM MST, rain has ended in the warned area. The public reports 
flash flooding of areas along Granite Creek near and downstream of 
downtown Prescott, including Granite Creek Park. River gages also 
show flash flooding is already occurring.

HAZARD...Life-threatening flash flooding.

SOURCE...Public and gage reported.

IMPACT...Life-threatening flash flooding of low-water crossings,
         creeks, normally dry washes and roads. Lowland overflow
         and minor flooding of trails in Watson Woods Riparian
         Preserve is possible over the next few hours.

Some locations that will experience flash flooding include...
  Chino Valley, Prescott, Oak Knoll Village, and White Spar 
  Campground.

This includes the following highways...
	State Route 69 between mile markers 295 and 296.
	State Route 89 between mile markers 309 and 332.
	State Route 89A between mile markers 318 and 319.

This includes the following creeks, washes and rivers...
  Verde River, Copper Basin Wash, Granite Creek, Mint Wash, Little 
  Chino Valley, Bottleneck Wash, Spence Creek, Willow Creek, Butte 
  Creek, Bannon Creek, and Miller Creek.

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 3451 11256 3455 11255 3465 11251 3474 11247
      3485 11245 3485 11239 3470 11237 3451 11244

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

NL

939 
WGUS55 KFGZ 190346
FFWFGZ
AZC025-190500-
/O.EXT.KFGZ.FF.W.0228.000000T0000Z-210919T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
846 PM MST Sat Sep 18 2021

The National Weather Service in Flagstaff has extended the

* Flash Flood Warning for...
  Granite Creek and other drainages in Prescott in...
  Yavapai County in west central Arizona...

* Until 1000 PM MST.

* At 840 PM MST, the warning has been extended another hour due to 
  continued elevated flows in Granite Creek being observed on river 
  gages producing minor flooding.

  HAZARD...Life-threatening flash flooding.

  SOURCE...Gage reported.

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

* Some locations that will experience flash flooding include...
  Prescott, Prescott Airport and Downtown Prescott.

This includes the following highways...
	State Route 69 between mile markers 295 and 296.
	State Route 89 between mile markers 312 and 320.
	State Route 89A between mile markers 318 and 319.

This includes the following creeks, washes and rivers...
  Granite Creek, Miller Creek, Bottleneck Wash, Willow Creek.

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 3454 11249 3456 11249 3462 11244 3479 11241
      3485 11245 3485 11239 3470 11237 3454 11243

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

NL

943 
WGUS75 KFGZ 190455
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
955 PM MST Sat Sep 18 2021

AZC025-190505-
/O.EXP.KFGZ.FF.W.0228.000000T0000Z-210919T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
955 PM MST Sat Sep 18 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 10 PM MST THIS EVENING FOR 
GRANITE CREEK NEAR PRESCOTT IN YAVAPAI COUNTY...

Granite Creek is still expected to have elevated flow over the next 
few hours, but flood waters will continue to retreat as water levels 
drop. Please continue to heed remaining road closures.

LAT...LON 3454 11249 3456 11249 3462 11244 3479 11241
      3485 11245 3485 11239 3470 11237 3454 11243

$$

NL

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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.