Alert archive / Hawaii / Flash Flood Warnings in 2021

Flash Flood Warning 15, NWS Honolulu, HI

March 9, 2021Honolulu County, Hawaii

NWS Honolulu, HI issued this flash flood warning at Mar 9, 2021, 10:31 AM HST for Honolulu County, Hawaii. It was in force for 6 hr. 4 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: Mar 9, 2021, 10:31 AM HST (20:31 UTC)
Expired: Mar 9, 2021, 4:45 PM HST
In force: 6 hr
Issued by: NWS Honolulu, HI
Area: Storm-based polygon
Flood severity: None

County Honolulu County, HI

The radar

The Molokai radar (PHMO), 75 km from the middle of the area, began a volume at 20:31 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
Mar 9, 10:35 AM HST	FLASH FLOOD	Kaneohe, HI	FOUR FEET OF WATER AT WILLIAN HENRY ROAD IN KANEOHE. BLOCKED DRAIN IN AREA. WATER GOING INTO HOUSES.
Mar 9, 11:15 AM HST	FLASH FLOOD	1 Nnw Kahaluu, HI	PARTIAL ROAD CLOSURE ON KAMEHAMEHA HWY BETWEEN WAILEHUA RD AND WAIKANE STORE. CONTRA-FLOW TRAFFIC IN THE AREA.
Mar 9, 1:35 PM HST	FLASH FLOOD	Pupukea, HI	RIVER/CREEK OVERFLOWING; CROPLAND/YARD/BASEMENT FLOODING.
Mar 9, 2:54 PM HST	FLASH FLOOD	Punaluu, HI	STREET/ROAD FLOODING; STREET/ROAD CLOSED; VEHICLES STRANDED.

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

The nearest sounding before it

Lihue, (PHLI), launched 12:00Z, 8.5 hours before the alert went out and 169 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: 198 J/kg
Mixed-layer CIN: -3 J/kg
Mixed-layer LCL: 585 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: 29 m²/s²
0-3 km storm-relative helicity: 39 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

475 
WGHW50 PHFO 092031
FFWHFO
HIC003-092345-
/O.NEW.PHFO.FF.W.0015.210309T2031Z-210309T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Honolulu HI
1031 AM HST Tue Mar 9 2021

The National Weather Service in Honolulu has issued a

* Flash Flood Warning for...
  The island of Oahu in Honolulu County

* Until 145 PM HST.

* At 1031 AM HST, radar and automated rain gauges indicated heavy 
  rain falling over windward Oahu. Rain was falling at a rate of 3 
  to 4 inches per hour. Flash flooding is occurring or expected to 
  begin shortly.

  HAZARD...Flash flooding caused by heavy rain.

  SOURCE...Radar and automated gauges.

  IMPACT...Flooding in drainages, streams, rivers, roads,
           properties, and other low-lying areas. Public road
           closures possible in some areas. Landslides are
           possible in steep terrain.

* Some locations that will experience flash flooding include...
  Waikane, Waiahole, Kahaluu, Kaaawa, Ahuimanu, Punaluu, Hauula, 
  Kaneohe, Kaneohe Marine Base, Wahiawa, Laie, Kalihi, Maunawili, 
  Kailua, Manoa, Kahuku, Palolo, Waimanalo, Haleiwa and Hawaii Kai.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Stay away from streams, rivers, drainage ditches, and culverts, even 
if they are currently dry.

Do not cross fast flowing or rising water in your vehicle, or on 
foot. Turn around, don't drown.

The heavy rains may cause rock and mudslides in steep terrain areas.

&&

This warning may need to be extended beyond 145 PM HST if flooding 
persists.

This Flash Flood Warning replaces the previously issued Flood 
Advisory that was in effect for The island of Oahu in Honolulu 
County.

LAT...LON 2162 15811 2173 15800 2173 15797 2155 15783
      2147 15783 2143 15779 2144 15778 2146 15779
      2147 15778 2147 15771 2141 15772 2134 15768
      2133 15763 2131 15763 2126 15768 2125 15771

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

DONALDSON

4 follow-up statements

052 
WGHW70 PHFO 092115
FFSHFO

Flash Flood Statement
National Weather Service Honolulu HI
1115 AM HST Tue Mar 9 2021

HIC003-092345-
/O.CON.PHFO.FF.W.0015.000000T0000Z-210309T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Honolulu HI-
1115 AM HST Tue Mar 9 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 145 PM HST THIS 
AFTERNOON FOR THE ISLAND OF OAHU IN HONOLULU COUNTY...

At 1115 AM HST, radar and automated rain gauges indicated that heavy 
rain was falling over windward Oahu. Rain continues to fall at a 
rate of 3 to 4 inches per hour. Flash flooding is occurring. The 
Waiahole Stream gaage is reporting a large rise. Flooding has been 
reported by emergency management officials along Willian Henry Road 
in Kaneohe and Okana Road Kahaluu.

HAZARD...Flash flooding caused by heavy rain.

SOURCE...Radar and automated gauges.

IMPACT...Flooding in drainages, streams, rivers, roads,
         properties, and other low-lying areas. Public road
         closures possible in some areas. Landslides are possible
         in steep terrain.

Some locations that will experience flash flooding include...
  Waikane, Waiahole, Kahaluu, Kaaawa, Ahuimanu, Punaluu, Hauula, 
  Kaneohe, Kaneohe Marine Base, Wahiawa, Laie, Kalihi, Maunawili, 
  Kailua, Manoa, Kahuku, Palolo, Waimanalo, Haleiwa and Hawaii Kai.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Stay away from streams, rivers, drainage ditches, and culverts, even 
if they are currently dry.

Do not cross fast flowing or rising water in your vehicle, or on 
foot. Turn around, don't drown.

The heavy rains may cause rock and mudslides in steep terrain areas.

&&

This warning may need to be extended beyond 145 PM HST if flooding 
persists.

LAT...LON 2162 15811 2173 15800 2173 15797 2155 15783
      2147 15783 2143 15779 2144 15778 2146 15779
      2147 15778 2147 15771 2141 15772 2134 15768
      2133 15763 2131 15763 2126 15768 2125 15771

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

DONALDSON

581 
WGHW70 PHFO 092130
FFSHFO

Flash Flood Statement
National Weather Service Honolulu HI
1130 AM HST Tue Mar 9 2021

HIC003-092345-
/O.CON.PHFO.FF.W.0015.000000T0000Z-210309T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Honolulu HI-
1130 AM HST Tue Mar 9 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 145 PM HST THIS 
AFTERNOON FOR THE ISLAND OF OAHU IN HONOLULU COUNTY...

At 1130 AM HST, Radar and rain gages continue to show rain falling 
at 3 to 4 inches per hour over windward Oahu. Emergency management 
officials report Kamehameha Highway closed in several locations due 
to flooding. There are additional road closures in windward Oahu 
from Kaneohe to Hauula.

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

SOURCE...Emergency management.

IMPACT...Significant and life threatening flooding in drainages,
         streams, rivers, roads, properties, and other low lying
         areas. Multiple public road closures expected, as well
         as landslides in steep terrain.

Some locations that will experience flash flooding include...
  Waikane, Waiahole, Kahaluu, Kaaawa, Ahuimanu, Punaluu, Hauula, 
  Kaneohe, Kaneohe Marine Base, Wahiawa, Laie, Kalihi, Maunawili, 
  Kailua, Manoa, Kahuku, Palolo, Waimanalo, Haleiwa and Hawaii Kai.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Stay away from streams, rivers, drainage ditches, and culverts, even 
if they are currently dry.

Do not cross fast flowing or rising water in your vehicle, or on 
foot. Turn around, don't drown.

The heavy rains may cause rock and mudslides in steep terrain areas.

&&

This warning may need to be extended beyond 145 PM HST if flooding 
persists.

LAT...LON 2162 15811 2173 15800 2173 15797 2155 15783
      2147 15783 2143 15779 2144 15778 2146 15779
      2147 15778 2147 15771 2141 15772 2134 15768
      2133 15763 2131 15763 2126 15768 2125 15771

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

$$

DONALDSON

899 
WGHW70 PHFO 092258
FFSHFO

Flash Flood Statement
National Weather Service Honolulu HI
1258 PM HST Tue Mar 9 2021

HIC003-092345-
/O.CON.PHFO.FF.W.0015.000000T0000Z-210309T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Honolulu HI-
1258 PM HST Tue Mar 9 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 145 PM HST THIS 
AFTERNOON FOR THE ISLAND OF OAHU IN HONOLULU COUNTY...

At 1258 PM HST, Radar and rain gages show rain falling at 2.5 to 3.5 
inches per hour over windward Oahu. Emergency management officials 
report Kamehameha Highway closed at Pipilani Place in Haaula. They 
report two homes with flood damage in the area.

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

SOURCE...Emergency management.

IMPACT...Significant and life threatening flooding in drainages,
         streams, rivers, roads, properties, and other low lying
         areas. Multiple public road closures expected, as well
         as landslides in steep terrain.

Some locations that will experience flash flooding include...
  Waikane, Waiahole, Kahaluu, Kaaawa, Ahuimanu, Punaluu, Hauula, 
  Kaneohe, Kaneohe Marine Base, Wahiawa, Laie, Kalihi, Maunawili, 
  Kailua, Manoa, Kahuku, Palolo, Waimanalo, Haleiwa and Hawaii Kai.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Stay away from streams, rivers, drainage ditches, and culverts, even 
if they are currently dry.

Do not cross fast flowing or rising water in your vehicle, or on 
foot. Turn around, don't drown.

The heavy rains may cause rock and mudslides in steep terrain areas.

&&

This warning may need to be extended beyond 145 PM HST if flooding 
persists.

LAT...LON 2162 15811 2173 15800 2173 15797 2155 15783
      2147 15783 2143 15779 2144 15778 2146 15779
      2147 15778 2147 15771 2141 15772 2134 15768
      2133 15763 2131 15763 2126 15768 2125 15771

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

$$

DONALDSON

688 
WGHW50 PHFO 092325
FFWHFO
HIC003-100245-
/O.EXT.PHFO.FF.W.0015.000000T0000Z-210310T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Honolulu HI
125 PM HST Tue Mar 9 2021

The National Weather Service in Honolulu has extended the

* Flash Flood Warning for...
  The island of Oahu in Honolulu County

* Until 445 PM HST.

* At 125 PM HST, Radar and rain gages continue to show rain falling 
  at 2.5 to 3.5 inches per hour over windward Oahu. Several roads 
  remain closed in the area.

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

  SOURCE...Emergency management.

  IMPACT...Significant and life threatening flooding in
           drainages, streams, rivers, roads, properties, and
           other low lying areas. Multiple public road closures
           expected, as well as landslides in steep terrain.

* Some locations that will experience flash flooding include...
  Waikane, Waiahole, Kahaluu, Kaaawa, Ahuimanu, Punaluu, Hauula, 
  Kaneohe, Kaneohe Marine Base, Wahiawa, Laie, Kalihi, Maunawili, 
  Kailua, Manoa, Kahuku, Palolo, Waimanalo, Haleiwa and Hawaii Kai.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Stay away from streams, rivers, drainage ditches, and culverts, even 
if they are currently dry.

Do not cross fast flowing or rising water in your vehicle, or on 
foot. Turn around, don't drown.

The heavy rains may cause rock and mudslides in steep terrain areas.

&&

This warning may need to be extended beyond 445 PM HST if flooding 
persists.

LAT...LON 2162 15811 2173 15800 2173 15797 2155 15783
      2147 15783 2143 15779 2144 15778 2146 15779
      2147 15778 2147 15771 2141 15772 2134 15768
      2133 15763 2131 15763 2126 15768 2125 15771

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

$$

DONALDSON

The office that day

Everything else NWS Honolulu, HI issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 8, 2:42 PM HST	Flash Flood Warning Considerable damage threat	HFO	Kalawao	5 hr
Mar 8, 8:07 PM HST	High Surf Advisory	HFO	Honolulu, Kalawao	19 hr
Mar 8, 9:32 PM HST	Areal Flood Advisory	HFO	Kalawao	33 min
Mar 8, 10:05 PM HST	Flash Flood Warning	HFO	Kalawao	5 hr
Mar 8, 10:55 PM HST	Areal Flood Advisory	HFO	Kauai	6 hr
Mar 9, 5:02 AM HST	Areal Flood Advisory	HFO	Honolulu	3 hr
Mar 9, 8:05 AM HST	Areal Flood Advisory	HFO	Honolulu	28 min
Mar 9, 8:09 AM HST	Special Marine Warning	HFO		2 hr
Mar 9, 8:22 AM HST	Special Weather Statement	HFO	Honolulu	53 min
Mar 9, 8:33 AM HST	Flash Flood Warning	HFO	Honolulu	117 min
Mar 9, 9:15 AM HST	Special Weather Statement	HFO	Honolulu	30 min
Mar 9, 9:59 AM HST	Special Weather Statement	HFO	Honolulu	61 min
Mar 9, 10:03 AM HST	Special Marine Warning	HFO		54 min
Mar 9, 10:55 AM HST	Areal Flood Advisory	HFO	Hawaii	11 hr

Nearby

Flash Flood Warnings in Hawaii, 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.