Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 9, NWS Hanford, CA

July 29, 2021Madera County, California

NWS Hanford, CA issued this flash flood warning at Jul 29, 2021, 5:20 PM PDT for Madera County, California. It was in force for 3 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 29, 2021, 5:20 PM PDT (00:20 UTC)
Expired: Jul 29, 2021, 7:50 PM PDT
In force: 3 hr
Issued by: NWS Hanford, CA
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Madera County, CA

The radar

The San Joaquin Valley radar (KHNX), 116 km from the middle of the area, began a volume at 00:23 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

Oakland, CA (KOAK), launched 00:00Z, 0.3 hours before the alert went out and 247 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: 2384 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 9 m²/s²
0-3 km storm-relative helicity: 79 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

311 
WGUS56 KHNX 300020
FFWHNX
CAC039-300315-
/O.NEW.KHNX.FF.W.0009.210730T0020Z-210730T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Joaquin Valley CA
520 PM PDT Thu Jul 29 2021

The National Weather Service in Hanford CA has issued a

* Flash Flood Warning for...
  Northeastern Madera County in central California...

* Until 815 PM PDT.

* At 516 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Up to one half to one inches of 
  rain have fallen. Flash flooding is ongoing or expected to begin 
  shortly.

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

  SOURCE...Radar indicated.

  IMPACT...Life threatening flash flooding of creeks and streams. 
           
  Excessive rainfall over the burn scar will result in debris flow.
 The debris flow can consist of rock, mud, vegetation and other 
loose materials.

* Flash flooding will remain over mainly rural areas of northeastern
  Madera County.
  Additional rainfall mounts of one half to one and a half inches of 
  are possible in the warned area.

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.

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

&&

LAT...LON 3740 11947 3739 11939 3734 11938 3729 11939
      3730 11946 3731 11948 3735 11949

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

An additional one half to one and a half inches of rain is expected 
over the next hour.

$$
CMc

2 follow-up statements

500 
WGUS76 KHNX 300132
FFSHNX

Flash Flood Statement
National Weather Service San Joaquin Valley CA
632 PM PDT Thu Jul 29 2021

CAC039-300315-
/O.CON.KHNX.FF.W.0009.000000T0000Z-210730T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Madera CA-
632 PM PDT Thu Jul 29 2021

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 815 PM PDT FOR
NORTHEASTERN MADERA COUNTY...

At 626 PM PDT, Doppler radar indicated that heavy rainfall over the 
Creek Fire burn scar has ended. Between one to two inches of rain 
has fallen over the last hour. Flash flooding and debris flows are 
ongoing or are expected to occur shortly.

HAZARD...Life threatening flash flooding. Heavy rain producing flash 
         flooding and debris flows.

SOURCE...Radar indicated.

IMPACT...Life threatening flash flooding of creeks and streams, 
         urban areas, highways, streets and underpasses.

Excessive rainfall over the burn scar will result in debris flows. 
The debris flow can consist of rock, mud, vegetation and other loose 
materials.



PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain alert for flooding even in locations not receiving rain.
Arroyos, streams, and rivers can become raging killer currents in a
matter of minutes, even from distant rainfall.

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.

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

&&

LAT...LON 3740 11947 3739 11939 3734 11938 3729 11939
      3730 11946 3731 11948 3735 11949

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

$$

CMc

530 
WGUS76 KHNX 300250
FFSHNX

Flash Flood Statement
National Weather Service San Joaquin Valley CA
750 PM PDT Thu Jul 29 2021

CAC039-300258-
/O.CAN.KHNX.FF.W.0009.000000T0000Z-210730T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Madera CA-
750 PM PDT Thu Jul 29 2021

...THE FLASH FLOOD WARNING FOR NORTHEASTERN MADERA COUNTY IS
CANCELLED...

The risk of flash flooding and debris flows are no longer expected 
to pose a threat. Please continue to heed any remaining road 
closures.

LAT...LON 3740 11947 3739 11939 3734 11938 3729 11939
      3730 11946 3731 11948 3735 11949

$$

CMc

The office that day

Everything else NWS Hanford, CA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 30, 2:52 PM PDT	Flash Flood Warning	HNX	Fresno, Madera	38 min
Jul 30, 3:30 PM PDT	Flash Flood Warning	HNX	Fresno, Madera, Mariposa	60 min
Jul 30, 4:02 PM PDT	Flash Flood Warning	HNX	Mariposa, Tuolumne	116 min
Jul 30, 4:08 PM PDT	Special Weather Statement	HNX	Mariposa	22 min
Jul 30, 4:20 PM PDT	Special Weather Statement	HNX	Tuolumne	40 min
Jul 30, 4:30 PM PDT	Special Weather Statement	HNX	Mariposa	45 min
Jul 30, 4:33 PM PDT	Flash Flood Warning	HNX	Mariposa	57 min

Nearby

Flash Flood Warnings in California, 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.