Urban and small stream flood advisory
Encyclopedia
An Urban and small stream flood advisory is issued when ponding
of water of streets, low-lying areas, highways, underpasses, urban storm drain
s, and elevation of creek and small stream levels is occurring or imminent. Urban and small stream flood advisories are issued for flooding that occurs within 3 hours after the excessive rainfall. These advisories are issued on a county by county basis by the local Weather Forecast Office and are generally in effect for 3 to 4 hours.
DRAINAGE AREAS IN
FOR THE FOLLOWING ISLANDS...
IN THE U.S. VIRGIN ISLANDS
SAINT JOHN AND SAINT THOMAS
ADVISORY AREA. ADDITIONAL RAINFALL AMOUNTS OF 1 TO 3 ARE POSSIBLE IN
THE ADVISORY AREA DURING THE NEXT COUPLE OF HOURS. EXCESSIVE RUNOFF
FROM WILL CAUSE FLOODING OF SMALL CREEKS AND GUTS...AND LOW SPOTS IN
HIGHWAYS. ADDITIONALLY...ROADS AND LAND ALONG THE BANKS OF CREEKS
AND STREAMS AND OTHER LOW LYING AREAS ARE SUBJECT TO FLOODING.
ALSO...MUDSLIDES ARE POSSIBLE IN AREAS OF STEEP TERRAIN.
MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN. MOVE TO
HIGHER GROUND.
&&
LAT...LON 1828 6470 1828 6499 1831 6508 1840 6508
1840 6466 1836 6463 1831 6463
$$
Ponding
Ponding is a term that refers to the unwanted pooling of water, typically on a flat roof.-Cause:Most flat roof systems are designed with a slight pitch to shed water off the sides, usually into a scupper system or into an internal drainage system. When a scupper or drain is clogged or fails for...
of water of streets, low-lying areas, highways, underpasses, urban storm drain
Storm drain
A storm drain, storm sewer , stormwater drain or drainage well system or simply a drain or drain system is designed to drain excess rain and ground water from paved streets, parking lots, sidewalks, and roofs. Storm drains vary in design from small residential dry wells to large municipal systems...
s, and elevation of creek and small stream levels is occurring or imminent. Urban and small stream flood advisories are issued for flooding that occurs within 3 hours after the excessive rainfall. These advisories are issued on a county by county basis by the local Weather Forecast Office and are generally in effect for 3 to 4 hours.
Example
FLOOD ADVISORY
NATIONAL WEATHER SERVICE SAN JUAN PR
110 PM AST TUE OCT 5 2010
VIC020-030-052015-
/O.NEW.TJSJ.FA.Y.0457.101005T1710Z-101005T2015Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAINT JOHN VI-SAINT THOMAS VI-
110 PM AST TUE OCT 5 2010
THE NATIONAL WEATHER SERVICE IN SAN JUAN HAS ISSUED AN
- URBAN AND SMALL STREAM FLOOD ADVISORY FOR MINOR FLOODING OF POOR
DRAINAGE AREAS IN
FOR THE FOLLOWING ISLANDS...
IN THE U.S. VIRGIN ISLANDS
SAINT JOHN AND SAINT THOMAS
- UNTIL 415 PM AST
- AT 109 PM AST...DOPPLER RADAR INDICATED PERSISTENT RAIN IN THE
ADVISORY AREA. ADDITIONAL RAINFALL AMOUNTS OF 1 TO 3 ARE POSSIBLE IN
THE ADVISORY AREA DURING THE NEXT COUPLE OF HOURS. EXCESSIVE RUNOFF
FROM WILL CAUSE FLOODING OF SMALL CREEKS AND GUTS...AND LOW SPOTS IN
HIGHWAYS. ADDITIONALLY...ROADS AND LAND ALONG THE BANKS OF CREEKS
AND STREAMS AND OTHER LOW LYING AREAS ARE SUBJECT TO FLOODING.
ALSO...MUDSLIDES ARE POSSIBLE IN AREAS OF STEEP TERRAIN.
MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN. MOVE TO
HIGHER GROUND.
&&
LAT...LON 1828 6470 1828 6499 1831 6508 1840 6508
1840 6466 1836 6463 1831 6463
$$
See also
- Severe weather terminology (United States)Severe weather terminology (United States)This article describes the United States National Weather Service severe weather terminology. The NWS defines precise meanings for nearly all its weather terms. This article describes NWS terminology and related NWS weather scales...
- Flash Flood WarningFlash Flood WarningA Flash Flood Warning is issued when a flash flood is imminent or occurring in the warned area. A flash flood is a sudden, violent flood after a heavy rain...