Alert archive / Guam / Flash Flood Warnings in 2021

Flash Flood Warning 2, NWS Guam

July 21, 2021

NWS Guam issued this flash flood warning at Jul 21, 2021, 11:23 PM CDT. 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 21, 2021, 11:23 PM CDT (04:23 UTC)
Expired: Jul 22, 2021, 2:30 AM CDT
In force: 3 hr
Issued by: NWS Guam
Area: Storm-based polygon
Flood severity: None

The text

As transmitted.

775 
WGMY50 PGUM 220423
FFWGUM
GUC010-220730-
/O.NEW.PGUM.FF.W.0002.210722T0423Z-210722T0730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Tiyan GU
223 PM ChST Thu Jul 22 2021

The National Weather Service in Tiyan has issued a

* Flash Flood Warning for...
  Guam Island in the Marianas...

* Until 530 PM ChST.

* At 223 PM ChST, Satellite estimates and rain gauge data indicate 
  thunderstorms producing heavy rain across the warned area. Between 
  1 and 3 inches of rain have fallen. Additional rainfall amounts of 
  2 to 4 inches are possible in the warned area. Flash flooding is 
  already occurring.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Satellite estimates and automated gauges.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Dededo, Tamuning, Yigo, Mangilao, Barrigada, Andersen AFB and 
  Mongmong-Toto-Maite.

This Flash Flood Warning is for the northern half of Guam.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 1348 14477 1349 14477 1350 14477 1350 14479
      1352 14480 1353 14480 1358 14483 1360 14484
      1362 14483 1365 14486 1365 14487 1364 14488
      1360 14490 1360 14495 1352 14492 1351 14489
      1349 14488 1348 14487 1344 14482

FLASH FLOOD...SATELLITE AND GAUGE INDICATED

$$

NS

The office that day

Everything else NWS Guam issued on the same UTC day.

Issued	Product	Office	Lasted
Jul 21, 11:05 PM CDT	Areal Flood Advisory	GUM	3 hr
Jul 21, 11:23 PM CDT	Flash Flood Watch	GUM	16 hr
Jul 22, 12:22 AM CDT	Areal Flood Advisory	GUM	113 min
Jul 22, 2:42 AM CDT	Areal Flood Advisory	GUM	2 hr
Jul 22, 2:20 PM CDT	High Surf Advisory	GUM	5 days

Nearby

Flash Flood Warnings in Guam, 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.