Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 9, NWS Phoenix, AZ

July 1, 2021Maricopa County, Arizona

NWS Phoenix, AZ issued this flash flood warning at Jul 1, 2021, 10:22 PM MST for Maricopa 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: Jul 1, 2021, 10:22 PM MST (05:22 UTC)
Expired: Jul 2, 2021, 2:15 AM MST
In force: 4 hr
Issued by: NWS Phoenix, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Maricopa County, AZ

The radar

The Phoenix radar (KIWA), 49 km from the middle of the area, began a volume at 05:24 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, 5.4 hours before the alert went out and 54 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: 140 J/kg
Mixed-layer CIN: -50 J/kg
Mixed-layer LCL: 3255 m above ground
0-6 km bulk shear: 3 kt
0-1 km storm-relative helicity: -6 m²/s²
0-3 km storm-relative helicity: 44 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

370 
WGUS55 KPSR 020522
FFWPSR
AZC013-020915-
/O.NEW.KPSR.FF.W.0009.210702T0522Z-210702T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
1022 PM MST Thu Jul 1 2021

The National Weather Service in Phoenix has issued a

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

* Until 215 AM MST.

* At 1022 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain over the Bush Fire Burn Scar. Between 0.5 and 1.25 
  inches of rain has fallen. Additional rainfall amounts up to 0.5 
  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 Mesquite Creek and Sycamore Creek. 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 Fire
           Burn Scar.

  SOURCE...Radar.

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

* Some locations that will experience flash flooding include...
  Sugarloaf Mountain.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move away from recently burned areas. Life-threatening flooding of 
creeks, roads and normally dry arroyos is likely. The heavy rains 
will likely trigger rockslides, mudslides and debris flows in steep 
terrain, especially in and around these areas.

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

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3368 11146 3367 11146 3367 11148 3364 11154
      3365 11156 3367 11157 3369 11156 3370 11155
      3372 11153 3375 11151 3376 11150 3376 11149
      3375 11147 3374 11144 3372 11144 3369 11143
      3369 11144 3368 11145

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

$$

Iniguez

3 follow-up statements

385 
WGUS75 KPSR 020626
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
1126 PM MST Thu Jul 1 2021

AZC013-020915-
/O.CON.KPSR.FF.W.0009.000000T0000Z-210702T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maricopa AZ-
1126 PM MST Thu Jul 1 2021

...FLASH FLOOD WARNING FOR THE BUSH FIRE BURN SCAR REMAINS IN EFFECT 
UNTIL 215 AM MST FRIDAY FOR MARICOPA COUNTY...

At 1126 PM MST, Doppler radar indicated thunderstorms producing 
heavy rain over the Bush Fire Burn Scar. Between 1 and 1.5 inches of 
rain have fallen. Additional rainfall amounts up to 0.25 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 Mesquite Wash and Sycamore Creek. 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 Fire Burn Scar.

SOURCE...Radar.

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

Some locations that will experience flash flooding include...
  Sugarloaf Mountain.

This includes the following highways...
	AZ Route 87 between mile markers 201 and 210.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move away from recently burned areas. Life-threatening flooding of 
creeks, roads and normally dry arroyos is likely. The heavy rains 
will likely trigger rockslides, mudslides and debris flows in steep 
terrain, especially in and around these areas.

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

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3368 11146 3367 11146 3367 11148 3364 11154
      3365 11156 3367 11157 3369 11156 3370 11155
      3372 11153 3375 11151 3376 11150 3376 11149
      3375 11147 3374 11144 3372 11144 3369 11143
      3369 11144 3368 11145

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

$$

Iniguez

993 
WGUS75 KPSR 020805
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
105 AM MST Fri Jul 2 2021

AZC013-020915-
/O.CON.KPSR.FF.W.0009.000000T0000Z-210702T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maricopa AZ-
105 AM MST Fri Jul 2 2021

...FLASH FLOOD WARNING FOR THE BUSH FIRE BURN SCAR REMAINS IN EFFECT 
UNTIL 215 AM MST EARLY THIS MORNING FOR MARICOPA COUNTY...

At 105 AM MST, Doppler radar indicated thunderstorms producing heavy 
rain over the Bush Fire Burn Scar. Between 1 and 1.5 inches of rain 
have fallen. Additional rainfall amounts up to 0.5 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. 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 Fire Burn Scar.

SOURCE...Radar.

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

Some locations that will experience flash flooding include...
  Sugarloaf Mountain.

This includes the following highways...
	AZ Route 87 between mile markers 201 and 210.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move away from recently burned areas. Life-threatening flooding of 
creeks, roads and normally dry arroyos is likely. The heavy rains 
will likely trigger rockslides, mudslides and debris flows in steep 
terrain, especially in and around these areas.

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

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3368 11146 3367 11146 3367 11148 3364 11154
      3365 11156 3367 11157 3369 11156 3370 11155
      3372 11153 3375 11151 3376 11150 3376 11149
      3375 11147 3374 11144 3372 11144 3369 11143
      3369 11144 3368 11145

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

$$

JS

129 
WGUS75 KPSR 020921
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
221 AM MST Fri Jul 2 2021

AZC013-020931-
/O.EXP.KPSR.FF.W.0009.000000T0000Z-210702T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maricopa AZ-
221 AM MST Fri Jul 2 2021

...FLASH FLOOD WARNING FOR THE BUSH FIRE BURN SCAR HAS EXPIRED FOR 
MARICOPA COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 3368 11146 3367 11146 3367 11148 3364 11154
      3365 11156 3367 11157 3369 11156 3370 11155
      3372 11153 3375 11151 3376 11150 3376 11149
      3375 11147 3374 11144 3372 11144 3369 11143
      3369 11144 3368 11145

$$

JS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 1, 8:16 PM MST	Flash Flood Warning Considerable damage threat	PSR	Gila	4 hr
Jul 1, 9:37 PM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa	4 hr
Jul 1, 9:57 PM MST	Special Weather Statement	PSR		48 min
Jul 2, 4:00 PM MST	Flash Flood Warning Considerable damage threat	PSR	Gila	4 hr
Jul 2, 4:12 PM MST	Special Weather Statement	PSR		33 min
Jul 2, 4:50 PM MST	Special Weather Statement	PSR	Gila	25 min

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.