Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 143, NWS Phoenix, AZ

August 11, 2021Gila County, Maricopa County, Arizona

NWS Phoenix, AZ issued this flash flood warning at Aug 11, 2021, 7:30 AM MST for Gila County, Maricopa County, Arizona. It was in force for 6 hr. 1 report 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: Aug 11, 2021, 7:30 AM MST (14:30 UTC)
Expired: Aug 11, 2021, 1:30 PM MST
In force: 6 hr
Issued by: NWS Phoenix, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Gila County, AZ, Maricopa County, AZ

The radar

The Phoenix radar (KIWA), 62 km from the middle of the area, began a volume at 14:31 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
Aug 11, 11:00 AM MST	FLASH FLOOD	9 N Saguaro Lake, AZ	THE USGS GAGE, SYCAMORE CREEK NEAR FORT MCDOWELL (SYCA3), MEASURED TWO RAPID RISES IN STREAMFLOW. A 2.73 FOOT RISE IN 15 MINUTES FROM 9:00-9:15 AM MST AND A 3.60 FOOT RISE IN 30 MINUTES FROM 10:30-11:30 AM MST, WITH PEAK FLOW REACHING 6.29 FEET.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Phoenix, AZ (KPSR), launched 12:00Z, 2.5 hours before the alert went out and 66 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: 735 J/kg
Mixed-layer CIN: -36 J/kg
Mixed-layer LCL: 905 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 12 m²/s²
0-3 km storm-relative helicity: 53 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

234 
WGUS55 KPSR 111430
FFWPSR
AZC007-013-111830-
/O.NEW.KPSR.FF.W.0143.210811T1430Z-210811T1830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
730 AM MST Wed Aug 11 2021

The National Weather Service in Phoenix has issued a

* Flash Flood Warning for...
  The Bush burn scar in...
  Gila County in east central Arizona...
  Maricopa County in south central Arizona...

* Until 1130 AM MST.

* At 730 AM MST, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain over the Bush Burn Scar. 
  Between 0.5 and 1.5 inches of rain have fallen. The expected 
  rainfall rate is 1 to 2 inches in 1 hour. Additional rainfall 
  amounts of 1 to 2 inches are possible in the warned area. Flash 
  flooding is ongoing or expected to begin shortly.

Excessive rainfall over the burn scar will result in debris flow 
moving through the Sycamore Creek, Reno Creek, and other small 
washes in the warned area. The debris flow can consist of rock, mud, 
vegetation and other loose materials.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding in and around the Bush Burn
           Scar.

  SOURCE...Radar and automated gauges.

  IMPACT...Life threatening flash flooding of areas in and around
           the Bush Burn Scar.

* Some locations that will experience flash flooding include...
  Round Valley, Sunflower, Ballantine Trailhead, Sugarloaf Mountain, 
  Punkin Center and Tonto Basin.

This includes the following highways...
	AZ Route 188 between mile markers 250 and 259.
	AZ Route 87 between mile markers 205 and 214.

This includes the following streams and drainages...
  Picadilla Creek, Verde River, East Fork Sycamore Creek, Boulder 
  Creek, Mesquite Wash, Camp Creek, Sycamore Creek, Cottonwood Creek 
  and Ironwood Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This is a life threatening situation. Heavy rainfall will cause 
extensive and severe flash flooding of creeks...streams...and 
ditches in the Bush Burn Scar. Severe debris flows can also be 
anticipated across roads. Roads and driveways may be washed away in 
places. If you encounter flood waters...climb to safety.

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3369 11134 3370 11146 3366 11158 3376 11155
      3383 11158 3387 11153 3398 11141 3397 11141
      3391 11129 3383 11124 3373 11120

FLASH FLOOD...RADAR AND GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR

$$

SDB

3 follow-up statements

533 
WGUS75 KPSR 111646
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
946 AM MST Wed Aug 11 2021

AZC007-013-111830-
/O.CON.KPSR.FF.W.0143.000000T0000Z-210811T1830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Gila AZ-Maricopa AZ-
946 AM MST Wed Aug 11 2021

...FLASH FLOOD WARNING FOR THE BUSH BURN SCAR REMAINS IN EFFECT 
UNTIL 1130 AM MST THIS MORNING FOR GILA AND MARICOPA COUNTIES...

At 946 AM MST, Doppler radar and automated rain gauges indicated 
thunderstorms producing heavy rain over the Bush Burn Scar. Between 
1 and 2.5 inches of rain have fallen. Additional rainfall amounts of 
1 to 2 inches are possible in the warned area. Flash flooding is 
ongoing or expected to begin shortly. A USGS gauge on Sycamore Creek 
near Fort McDowell has seen a rapid 3 foot rise in the last 45 
minutes.

Excessive rainfall over the burn scar will result in debris flow 
moving through the Sycamore Creek, Reno Creek, and other washes. The 
debris flow can consist of rock, mud, vegetation and other loose 
materials.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding in and around the Bush Burn Scar.

SOURCE...Radar and automated gauges.

IMPACT...Life threatening flash flooding of areas in and around
         the Bush Burn Scar.

Some locations that will experience flash flooding include...
  Round Valley, Sunflower, Ballantine Trailhead, Sugarloaf Mountain, 
  Punkin Center and Tonto Basin.

This includes the following highways...
	AZ Route 188 between mile markers 250 and 259.
	AZ Route 87 between mile markers 205 and 214.

This includes the following streams and drainages...
  Picadilla Creek, Verde River, East Fork Sycamore Creek, Boulder 
  Creek, Mesquite Wash, Camp Creek, Sycamore Creek, Cottonwood Creek 
  and Ironwood Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This is a life threatening situation. Heavy rainfall will cause 
extensive and severe flash flooding of creeks...streams...and 
ditches in the Bush Burn Scar. Severe debris flows can also be 
anticipated across roads. Roads and driveways may be washed away in 
places. If you encounter flood waters...climb to safety.

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3369 11134 3370 11146 3366 11158 3376 11155
      3383 11158 3387 11153 3398 11141 3397 11141
      3391 11129 3383 11124 3373 11120

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

$$

SDB

630 
WGUS55 KPSR 111819
FFWPSR
AZC007-013-112030-
/O.EXT.KPSR.FF.W.0143.000000T0000Z-210811T2030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
1119 AM MST Wed Aug 11 2021

The National Weather Service in Phoenix has extended the

* Flash Flood Warning for...
  The Bush burn scar in...
  Gila County in east central Arizona...
  Maricopa County in south central Arizona...

* Until 130 PM MST.

* At 1119 AM MST, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain over the Bush Burn Scar. 
  Between 1 and 2.5 inches of rain have fallen. Additional rainfall 
  amounts of 1 to 2 inches are possible in the warned area. Flash 
  flooding is ongoing or expected to begin shortly. A USGS gauge on 
  Sycamore Creek near Fort McDowell has seen a another rapid 3 foot 
  rise and is now running around 6 feet.

Excessive rainfall over the burn scar will result in debris flow 
moving through the Sycamore Creek, Reno Creek, and other washes. The 
debris flow can consist of rock, mud, vegetation and other loose 
materials.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding in and around the Bush Burn
           Scar.

  SOURCE...Gauges reported.

  IMPACT...Life threatening flash flooding of areas in and around
           the Bush Burn Scar.

* Some locations that will experience flash flooding include...
  Round Valley, Sunflower, Ballantine Trailhead, Sugarloaf Mountain, 
  Punkin Center and Tonto Basin.

This includes the following highways...
	AZ Route 188 between mile markers 250 and 259.
	AZ Route 87 between mile markers 205 and 214.

This includes the following streams and drainages...
  Picadilla Creek, Verde River, East Fork Sycamore Creek, Boulder 
  Creek, Mesquite Wash, Camp Creek, Sycamore Creek, Cottonwood Creek 
  and Ironwood Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This is a life threatening situation. Heavy rainfall will cause 
extensive and severe flash flooding of creeks...streams...and 
ditches in the Bush Burn Scar. Severe debris flows can also be 
anticipated across roads. Roads and driveways may be washed away in 
places. If you encounter flood waters...climb to safety.

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3369 11134 3370 11146 3366 11158 3376 11155
      3383 11158 3387 11153 3398 11141 3397 11141
      3391 11129 3383 11124 3373 11120

FLASH FLOOD...GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

SDB

751 
WGUS75 KPSR 112030
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
130 PM MST Wed Aug 11 2021

AZC007-013-112040-
/O.EXP.KPSR.FF.W.0143.000000T0000Z-210811T2030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Gila AZ-Maricopa AZ-
130 PM MST Wed Aug 11 2021

...FLASH FLOOD WARNING FOR THE BUSH BURN SCAR HAS EXPIRED FOR GILA 
AND MARICOPA COUNTIES...

Flood waters have begun receding, but elevated flows continue in 
Sycamore Creek and into the Verde River, as well as in Tonto Creek. 
The heavy rain has ended. A Flood Warning has been issued for 
Sycamore Creek and Verde River. Please continue to heed remaining 
road closures.

LAT...LON 3369 11134 3370 11146 3366 11158 3376 11155
      3383 11158 3387 11153 3398 11141 3397 11141
      3391 11129 3383 11124 3373 11120

$$

SDB

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 10, 5:23 PM MST	Areal Flood Advisory	PSR	Maricopa	3 hr
Aug 10, 5:35 PM MST	Special Weather Statement	PSR		40 min
Aug 10, 5:51 PM MST	Areal Flood Advisory	PSR	La Paz	3 hr
Aug 10, 5:55 PM MST	Special Weather Statement	PSR	La Paz	50 min
Aug 10, 6:30 PM MST	Severe Thunderstorm Warning	PSR	La Paz, Yuma	45 min
Aug 10, 6:36 PM MST	Flash Flood Warning Considerable damage threat	PSR	La Paz, Maricopa	4 hr
Aug 10, 7:15 PM MST	Dust Storm Warning	PSR	La Paz, Yuma	60 min
Aug 10, 7:26 PM MST	Severe Thunderstorm Warning	PSR	La Paz, Maricopa, Yuma	49 min
Aug 10, 7:33 PM MST	Flash Flood Warning Considerable damage threat	PSR	La Paz, Yuma	4 hr
Aug 10, 7:43 PM MST	Dust Storm Advisory	PSR	Maricopa, Pinal, Yuma	62 min
Aug 10, 8:18 PM MST	Severe Thunderstorm Warning	PSR	La Paz, Yuma	57 min
Aug 10, 8:38 PM MST	Dust Storm Warning	PSR	La Paz, Yuma	52 min
Aug 10, 9:08 PM MST	Flash Flood Warning Considerable damage threat	PSR	La Paz, Yuma	6 hr
Aug 10, 9:12 PM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa, Yuma	6 hr
Aug 10, 9:23 PM MST	Special Weather Statement	PSR	Yuma	97 min
Aug 10, 9:42 PM MST	Dust Storm Warning	PSR	Yuma	93 min
Aug 10, 10:35 PM MST	Flash Flood Warning Considerable damage threat	PSR	La Paz, Maricopa, Yuma	6 hr
Aug 11, 12:01 AM MST	Flash Flood Warning Considerable damage threat	PSR	La Paz, Yuma	5 hr
Aug 11, 2:00 AM MST	Areal Flood Advisory	PSR	Gila	3 hr
Aug 11, 3:29 AM MST	Areal Flood Advisory	PSR	Maricopa	3 hr
Aug 11, 4:33 AM MST	Areal Flood Advisory	PSR	Maricopa, Pinal	3 hr
Aug 11, 6:06 AM MST	Areal Flood Advisory	PSR	Maricopa	3 hr
Aug 11, 6:11 AM MST	Areal Flood Advisory	PSR	Maricopa, Pinal	3 hr
Aug 11, 6:15 AM MST	Areal Flood Advisory	PSR	Gila, Maricopa	3 hr
Aug 11, 7:46 AM MST	Areal Flood Advisory	PSR	Maricopa, Pinal	3 hr
Aug 11, 8:12 AM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa, Pinal	6 hr
Aug 11, 9:13 AM MST	Areal Flood Advisory	PSR	Maricopa	3 hr
Aug 11, 1:01 PM MST	Special Weather Statement	PSR	Yuma	59 min
Aug 11, 1:29 PM MST	Areal Flood Warning	PSR	Maricopa	6 hr
Aug 11, 1:43 PM MST	Areal Flood Warning	PSR	Gila	4 hr
Aug 11, 1:49 PM MST	Areal Flood Advisory	PSR	Yuma	3 hr
Aug 11, 2:01 PM MST	Dust Storm Advisory	PSR	Yuma	59 min
Aug 11, 2:17 PM MST	Severe Thunderstorm Warning	PSR	Yuma	43 min
Aug 11, 3:02 PM MST	Flash Flood Warning Considerable damage threat	PSR	Yuma	4 hr
Aug 11, 3:11 PM MST	Special Weather Statement	PSR		64 min
Aug 11, 3:29 PM MST	Special Weather Statement	PSR	Maricopa	46 min
Aug 11, 3:34 PM MST	Special Weather Statement	PSR		56 min
Aug 11, 3:44 PM MST	Areal Flood Advisory	PSR	Maricopa	3 hr
Aug 11, 3:47 PM MST	Areal Flood Advisory	PSR	Maricopa	14 min
Aug 11, 3:50 PM MST	Areal Flood Advisory	PSR	Maricopa	3 hr
Aug 11, 4:01 PM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa	3 hr
Aug 11, 4:33 PM MST	Areal Flood Advisory	PSR	Maricopa	3 hr
Aug 11, 4:44 PM MST	Dust Storm Advisory	PSR	Maricopa, Pinal	61 min
Aug 11, 4:56 PM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa	3 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.