Alert archive / Hawaii / Flash Flood Warnings in 2021

Flash Flood Warning 11, NWS Honolulu, HI

March 8, 2021Kalawao County, Hawaii

NWS Honolulu, HI issued this flash flood warning at Mar 8, 2021, 11:15 AM HST for Kalawao County, Hawaii. It was in force for 7 hr. 3 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 8, 2021, 11:15 AM HST (21:15 UTC)
Expired
Mar 8, 2021, 6:15 PM HST
In force
7 hr
Issued by
NWS Honolulu, HI
Area
Storm-based polygon
Flood severity
None

County Kalawao County, HI

The radar

The Kamuela/Kohala Apt radar (PHKM), 86 km from the middle of the area, began a volume at 21:17 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

TimeReportWhereRemark
Mar 8, 12:52 PM HSTHEAVY RAIN 5.961 Ne Kokomo, HIRAIN SINCE 7 AM. ALSO REPORTS STANDING WATER ALONG PORTIONS OF HALEAKALA HIGHWAY. ESTIMATED DEPTH AROUND 4 TO 6 INCHES.
Mar 8, 2:20 PM HSTFLASH FLOOD2 N Kaupakulua, HIMAUI COUNTY EMERGENCY MANAGEMENT AGENCY RELAYS REPORTS THAT WATER HAS OVERTOPED THE KAUPAKULUA DAM. NUMEROUS EVACUATIONS HAVE BEEN ORDERED DOWNSTREAM OF THE DAM IN HAIKU AND PAUWELA.
Mar 8, 4:58 PM HSTFLASH FLOOD2 N Kaupakulua, HIMAUI COUNTY EMERGENCY MANAGEMENT AGENCY REPORTS THAT THE HANA HIGHWAY IS CLOSED FROM PEAHI RD NEAR HAIKU TO KEANAE.

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

The nearest sounding before it

Hilo, (PITO), launched 12:00Z, 9.3 hours before the alert went out and 171 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-pSkew-T log-p diagram, Hilo, at 12:00Z on 2021-03-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 99 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Hilo, at 12:00Z on 2021-03-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -18 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
99 J/kg
Mixed-layer CIN
-35 J/kg
Mixed-layer LCL
984 m above ground
0-6 km bulk shear
6 kt
0-1 km storm-relative helicity
-18 m²/s²
0-3 km storm-relative helicity
-16 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

287 
WGHW50 PHFO 082115
FFWHFO
HIC009-090015-
/O.NEW.PHFO.FF.W.0011.210308T2115Z-210309T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Honolulu HI
1115 AM HST Mon Mar 8 2021

The National Weather Service in Honolulu has issued a

* Flash Flood Warning for...
  The island of Maui in Maui County

* Until 215 PM HST.

* At 1115 AM HST, radar and automated rain gauges indicated heavy 
  rain falling over windward Haleakala. Rain was falling at a rate 
  of 2 to 3 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...
  Keanae, Nahiku, Kipahulu, Kaupo, Huelo, Kula, Hana, Makawao, 
  Pukalani, Haiku-Pauwela, Haliimaile, Pauwela, Paia, Haleakala 
  National Park, Wailua, Kailua and Hamoa.

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.

&&

This warning may need to be extended beyond 215 PM HST if flooding 
persists.

LAT...LON 2083 15636 2095 15635 2096 15632 2095 15624
      2087 15613 2087 15612 2085 15612 2084 15611
      2081 15599 2077 15597 2070 15597 2064 15604
      2061 15613 2062 15619

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

FOSTER
4 follow-up statements
706 
WGHW70 PHFO 082241
FFSHFO

Flash Flood Statement
National Weather Service Honolulu HI
1241 PM HST Mon Mar 8 2021

HIC009-090015-
/O.CON.PHFO.FF.W.0011.000000T0000Z-210309T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maui HI-
1241 PM HST Mon Mar 8 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 215 PM HST THIS 
AFTERNOON FOR THE ISLAND OF MAUI IN MAUI COUNTY...

At 1241 PM HST, radar and automated rain gauges indicated that heavy 
rain was falling over windward Haleakala. Water was reported flowing 
over the Hana Highway at Wailua. Rain was falling at a rate of 2 to 
3 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...
  Keanae, Nahiku, Kipahulu, Kaupo, Huelo, Kula, Hana, Makawao, 
  Pukalani, Haiku-Pauwela, Haliimaile, Pauwela, Paia, Haleakala 
  National Park, Wailua, Kailua and Hamoa.

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.

&&

This warning may need to be extended beyond 215 PM HST if flooding 
persists.

LAT...LON 2083 15636 2095 15635 2096 15632 2095 15624
      2087 15613 2087 15612 2085 15612 2084 15611
      2081 15599 2077 15597 2070 15597 2064 15604
      2061 15613 2062 15619

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

FOSTER
644 
WGHW50 PHFO 090008
FFWHFO
HIC009-090415-
/O.EXT.PHFO.FF.W.0011.000000T0000Z-210309T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Honolulu HI
208 PM HST Mon Mar 8 2021

The National Weather Service in Honolulu has extended the

* Flash Flood Warning for...
  The island of Maui in Maui County

* Until 615 PM HST.

* At 208 PM HST, radar and automated rain gauges indicated that 
  heavy rain was falling over windward Haleakala. Water was reported 
  flowing over the Hana Highway at Wailua. Rain was falling at a 
  rate of 2 to 3 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...
  Keanae, Nahiku, Kipahulu, Kaupo, Huelo, Kula, Hana, Makawao, 
  Pukalani, Haiku-Pauwela, Haliimaile, Pauwela, Paia, Haleakala 
  National Park, Wailua, Kailua and Hamoa.

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.

&&

This warning may need to be extended beyond 615 PM HST if flooding 
persists.

LAT...LON 2083 15636 2095 15635 2096 15632 2095 15624
      2087 15613 2087 15612 2085 15612 2084 15611
      2081 15599 2077 15597 2070 15597 2064 15604
      2061 15613 2062 15619

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

FOSTER
322 
WGHW70 PHFO 090235
FFSHFO

Flash Flood Statement
National Weather Service Honolulu HI
435 PM HST Mon Mar 8 2021

HIC009-090415-
/O.CON.PHFO.FF.W.0011.000000T0000Z-210309T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maui HI-
435 PM HST Mon Mar 8 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 615 PM HST THIS 
EVENING FOR THE ISLAND OF MAUI IN MAUI COUNTY...

At 435 PM HST, emergency management reports multiple road closures 
across upcountry communities and windward east Maui and has ordered 
evacuations near and down slope of the Kaupakalua Dam in Haiku and 
Pauwela. Hana Highway is closed near Pauwela, and east Maui is not 
accessible. Rain has diminished across upcountry areas but is 
falling at rates of 1 to 3 inches per hour near Hana.

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...
  Keanae, Nahiku, Kipahulu, Kaupo, Huelo, Kula, Hana, Makawao, 
  Pukalani, Haiku-Pauwela, Haliimaile, Pauwela, Paia, Haleakala 
  National Park, Wailua, Kailua and Hamoa.

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.

&&

This warning may need to be extended beyond 615 PM HST if flooding 
persists.

LAT...LON 2083 15636 2095 15635 2096 15632 2095 15624
      2087 15613 2087 15612 2085 15612 2084 15611
      2081 15599 2077 15597 2070 15597 2064 15604
      2061 15613 2062 15619

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

$$

WROE
035 
WGHW70 PHFO 090351
FFSHFO

Flash Flood Statement
National Weather Service Honolulu HI
551 PM HST Mon Mar 8 2021

HIC009-090415-
/O.CON.PHFO.FF.W.0011.000000T0000Z-210309T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maui HI-
551 PM HST Mon Mar 8 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 615 PM HST THIS 
EVENING FOR THE ISLAND OF MAUI IN MAUI COUNTY...

At 551 PM HST, radar indicated that heavy rainfall over windward and 
upcountry Maui has diminished. However, runoff remains high, and 
multiple roads across windward and upcountry Maui remain closed, 
including the Hana Highway between Keanae and Peahi Road near Haiku. 
Maui County officials are continuing evacuations in the Haiku and 
Pauwela areas down slope of the Kaupakalua Dam.

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

SOURCE...Radar indicated.

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...
  Keanae, Nahiku, Kipahulu, Kaupo, Huelo, Kula, Hana, Makawao, 
  Pukalani, Haiku-Pauwela, Haliimaile, Pauwela, Paia, Haleakala 
  National Park, Wailua, Kailua and Hamoa.

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.

&&

This warning may need to be extended beyond 615 PM HST if flooding 
persists.

LAT...LON 2083 15636 2095 15635 2096 15632 2095 15624
      2087 15613 2087 15612 2085 15612 2084 15611
      2081 15599 2077 15597 2070 15597 2064 15604
      2061 15613 2062 15619

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

$$

WROE

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 7, 3:20 PM HSTWinter Weather AdvisoryHFOHawaii4 days
Mar 7, 3:55 PM HSTHigh Surf AdvisoryHFOHonolulu, Kalawao24 hr
Mar 7, 5:22 PM HSTAreal Flood AdvisoryHFOHawaii6 hr
Mar 8, 8:45 AM HSTSpecial Marine WarningHFO45 min
Mar 8, 10:04 AM HSTAreal Flood AdvisoryHFOKalawao3 hr
Mar 8, 1:09 PM HSTAreal Flood AdvisoryHFOHawaii12 hr

Nearby

Flash Flood Warnings in Hawaii, 2021Every 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.