Alert archive / Hawaii / Flash Flood Warnings in 2021
Flash Flood Warning 38, NWS Honolulu, HI
NWS Honolulu, HI issued this flash flood warning at Oct 12, 2021, 2:26 AM HST for Hawaii County, Hawaii. It was in force for 6 hr. 2 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
- Oct 12, 2021, 2:26 AM HST (12:26 UTC)
- Expired
- Oct 12, 2021, 7:58 AM HST
- In force
- 6 hr
- Issued by
- NWS Honolulu, HI
- Area
- Storm-based polygon
- Flood severity
- None
County Hawaii County, HI
The radar
The Kamuela/Kohala Apt radar (PHKM), 57 km from the middle of the area, began a volume at 12:31 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 |
|---|---|---|---|
| Oct 12, 6:45 AM HST | FLASH FLOOD | Hilo, HI | ONE LANE OF KAMEHAMEHA AVENUE IN HILO REMAINS CLOSED DUE TO FLOODING. |
| Oct 12, 7:27 AM HST | FLASH FLOOD | 24 Wnw Hilo, HI | MAUNA KEA ACCESS ROAD HAS MULTIPLE LOCATIONS WITH BEBRIS ON ROAD BETWEEN DANIEL INOUYE HWY AND HALE POHAKU DUE TO OVERNIGHT RAIN. THE ROAD ALSO REMAINS CLOSED ABOVE HALE POHAKU. |
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, 0.4 hours before the alert went out and 36 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.
- Mixed-layer CAPE
- 707 J/kg
- Mixed-layer CIN
- 0 J/kg
- Mixed-layer LCL
- 507 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 30 m²/s²
- 0-3 km storm-relative helicity
- 50 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.6
The text
As transmitted.
060
WGHW50 PHFO 121226
FFWHFO
HIC001-121515-
/O.NEW.PHFO.FF.W.0038.211012T1226Z-211012T1515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Honolulu HI
226 AM HST Tue Oct 12 2021
The National Weather Service in Honolulu has issued a
* Flash Flood Warning for...
The island of Hawaii in Hawaii County
* Until 515 AM HST.
* At 226 AM HST, radar indicated heavy rain across the Hamakua coast
including the Hilo area. Rain was falling at a rate of 2 to 4
inches per hour. The Honolii Stream has risen to levels that could
lead to road closures and significant flooding in Hilo and the
surrounding area. The Wailuku river is also elevated that could
cause problems to its surrounding area as well.
HAZARD...Flash flooding caused by heavy rain.
SOURCE...Radar.
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...
Hilo, Hawaiian Paradise Park, Honokaa, Laupahoehoe, Ookala,
Paauilo, Ninole, Honomu, Hakalau, Pepeekeo, Papaikou, Kamuela,
Mountain View, Glenwood, Volcano, Kukuihaele, Waipio Valley, Keaau
and Waimanu Valley.
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 515 AM HST if flooding
persists.
LAT...LON 2011 15588 2022 15571 2014 15559 2011 15545
1999 15521 1986 15507 1976 15508 1975 15499
1965 15497 1962 15492 1958 15491 1941 15532
1973 15543
FLASH FLOOD...RADAR INDICATED
$$
LAU3 follow-up statements
623
WGHW50 PHFO 121503
FFWHFO
HIC001-121815-
/O.EXT.PHFO.FF.W.0038.000000T0000Z-211012T1815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Honolulu HI
503 AM HST Tue Oct 12 2021
The National Weather Service in Honolulu has extended the
* Flash Flood Warning for...
The island of Hawaii in Hawaii County
* Until 815 AM HST.
* At 503 AM HST, radar indicated pockets of moderate to heavy rain
across the Hamakua coast including the Hilo and Puna districts.
Rain was falling at a rate up to 1 inch per hour. Although the
widespread heavy rains have abated, the Honolii Stream and Wailuku
River remains swollen and elevated. This is on top of 3 to 6
inches of rain overnight across the Hamakua coast and in the Hilo
and Puna districts. Any additional downpours could lead to road
closures and significant flooding particularly the Hilo and
surrounding area.
HAZARD...Flash flooding caused by heavy rain.
SOURCE...Radar.
IMPACT...Flooding in drainages, streams, rivers, roads,
properties, and other low-lying areas. Public road
closures possible in some areas. Landslides are
possible in steep terrain.
* Some locations that will experience flash flooding include...
Hilo, Hawaiian Paradise Park, Honokaa, Laupahoehoe, Ookala,
Paauilo, Ninole, Honomu, Hakalau, Pepeekeo, Papaikou, Kamuela,
Mountain View, Glenwood, Volcano, Kukuihaele, Waipio Valley, Keaau
and Waimanu Valley.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Stay away from streams, rivers, drainage ditches, and culverts, even
if they are currently dry.
Do not cross fast flowing or rising water in your vehicle, or on
foot. Turn around, don't drown.
&&
This warning may need to be extended beyond 815 AM HST if flooding
persists.
LAT...LON 2011 15588 2022 15571 2014 15559 2011 15545
1999 15521 1986 15507 1976 15508 1975 15499
1965 15497 1962 15492 1958 15491 1941 15532
1973 15543
FLASH FLOOD...RADAR INDICATED
$$
LAU715
WGHW70 PHFO 121653
FFSHFO
Flash Flood Statement
National Weather Service Honolulu HI
653 AM HST Tue Oct 12 2021
HIC001-121815-
/O.CON.PHFO.FF.W.0038.000000T0000Z-211012T1815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hawaii HI-
653 AM HST Tue Oct 12 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 815 AM HST THIS
MORNING FOR THE ISLAND OF HAWAII IN HAWAII COUNTY...
At 653 AM HST, radar and gages indicated heavy showers over windward
Big Island have decreased considerably, with rain rates down below 1
inch per hour in most locations. Streams are declining but remain
high, and runoff continues to pose a hazard. Emergency management
reports that one lane of Kamehameha Avenue in Hilo remains closed.
HAZARD...Flash flooding caused by heavy rain.
SOURCE...Radar.
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...
Hilo, Hawaiian Paradise Park, Honokaa, Laupahoehoe, Ookala,
Paauilo, Ninole, Honomu, Hakalau, Pepeekeo, Papaikou, Kamuela,
Mountain View, Glenwood, Volcano, Kukuihaele, Waipio Valley, Keaau
and Waimanu Valley.
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.
&&
LAT...LON 2011 15588 2022 15571 2014 15559 2011 15545
1999 15521 1986 15507 1976 15508 1975 15499
1965 15497 1962 15492 1958 15491 1941 15532
1973 15543
FLASH FLOOD...RADAR INDICATED
$$
WROE630
WGHW70 PHFO 121758
FFSHFO
Flash Flood Statement
National Weather Service Honolulu HI
758 AM HST Tue Oct 12 2021
HIC001-121808-
/O.CAN.PHFO.FF.W.0038.000000T0000Z-211012T1815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hawaii HI-
758 AM HST Tue Oct 12 2021
...FLASH FLOOD WARNING IS CANCELLED FOR THE ISLAND OF HAWAII IN
HAWAII COUNTY...
Heavy rainfall has diminished, and high flow in streams is slowly
decreasing. Runoff will continue to decrease over the next couple of
hours, but flooding is no longer expected to pose a threat.
LAT...LON 2011 15588 2022 15571 2014 15559 2011 15545
1999 15521 1986 15507 1976 15508 1975 15499
1965 15497 1962 15492 1958 15491 1941 15532
1973 15543
$$
WROEThe office that day
Everything else NWS Honolulu, HI issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 11, 7:19 PM HST | Areal Flood Advisory | HFO | Hawaii | 3 hr |
| Oct 11, 11:16 PM HST | Areal Flood Advisory | HFO | Hawaii | 3 hr |
| Oct 12, 2:09 AM HST | Areal Flood Advisory | HFO | Hawaii | 6 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.