Alert archive / Louisiana / Flash Flood Warnings in 2021

Flash Flood Warning 47, NWS New Orleans, LA

May 21, 2021Iberville Parish, Louisiana

NWS New Orleans, LA issued this flash flood warning at May 21, 2021, 11:50 AM CDT for Iberville Parish, Louisiana. It was in force for 6 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: May 21, 2021, 11:50 AM CDT (16:50 UTC)
Expired: May 21, 2021, 5:45 PM CDT
In force: 6 hr
Issued by: NWS New Orleans, LA
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: Unknown

County Iberville Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 4.8 hours before the alert went out and 161 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: 19 J/kg
Mixed-layer CIN: -105 J/kg
Mixed-layer LCL: 761 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 98 m²/s²
0-3 km storm-relative helicity: 178 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

778 
WGUS54 KLIX 211650
FFWLIX
LAC047-212245-
/O.NEW.KLIX.FF.W.0047.210521T1650Z-210521T2245Z/
/00000.U.DM.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service New Orleans LA
1150 AM CDT Fri May 21 2021

The National Weather Service in New Orleans has issued a

* Flash Flood Warning for...
  A Dam Break below Aqua Dam on J R Drive in...
  South Central Iberville Parish in southeastern Louisiana...

* Until 545 PM CDT.

* At 1150 AM CDT, Iberville Emergency Operation Center reported the 
  failure of Aqua Dam on J R Drive causing flash flooding downstream 
  of State Highway 404.

  HAZARD...Life threatening flash flooding from the failure of
           Aqua Dam on J R Drive.

  SOURCE...Iberville Emergency Management

  IMPACT...Life threatening flash flooding of areas downstream
           from the Aqua Dam on J R Drive south of State Highway
           404.

* Some locations that will experience flash flooding include...
  Bayou Pigeon.

This includes the following streams and drainages...
  Tigre, Bayou, Lower Grand River and Goula, Bayou.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you are in low lying areas below the Aqua Dam on J R Drive you 
should move to higher ground immediately.

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

Move to higher ground now. Act quickly to protect your life.

&&

LAT...LON 3019 9148 3020 9147 3019 9129 3009 9121
      3005 9116 3003 9122 3004 9123 3003 9124
      3006 9127 3006 9134 3006 9137 3008 9137
      3010 9139 3010 9146 3011 9147 3013 9146
      3014 9147 3017 9147 3019 9147

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
DAM FAILURE...OCCURRING

$$

ME

1 follow-up statement

983 
WGUS74 KLIX 212250
FFSLIX

Flash Flood Statement
National Weather Service New Orleans LA
550 PM CDT Fri May 21 2021

LAC047-212300-
/O.EXP.KLIX.FF.W.0047.000000T0000Z-210521T2245Z/
/00000.U.DM.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Iberville LA-
550 PM CDT Fri May 21 2021

...FLASH FLOOD WARNING FOR THE FAILURE OF AQUA DAM ON J R DRIVE HAS 
BEEN REPLACED BY AN AREAL FLOOD WARNING FOR SOUTH CENTRAL IBERVILLE 
PARISH...

Flooding is continuing. Please continue to heed emergency management 
and parish orders.

LAT...LON 3019 9148 3020 9147 3019 9129 3009 9121
      3005 9116 3003 9122 3004 9123 3003 9124
      3006 9127 3006 9134 3006 9137 3008 9137
      3010 9139 3010 9146 3011 9147 3013 9146
      3014 9147 3017 9147 3019 9147

$$

CAB

The office that day

Everything else NWS New Orleans, LA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 20, 9:07 PM CDT	Special Marine Warning	LIX		83 min
May 21, 11:24 AM CDT	Special Marine Warning	LIX		96 min
May 21, 12:51 PM CDT	Special Marine Warning	LIX		84 min
May 21, 2:08 PM CDT	Special Marine Warning	LIX		97 min
May 21, 5:49 PM CDT	Areal Flood Warning	LIX	Iberville	14 hr

Nearby

Flash Flood Warnings in Louisiana, 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.