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000 

WGUS76 KSGX 180731

FFSSGX



FLASH FLOOD STATEMENT

NATIONAL WEATHER SERVICE SAN DIEGO CA

1131 PM PST FRI FEB 17 2006



CAC059-180745-

ORANGE CA-

1131 PM PST FRI FEB 17 2006



...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1145 PM PST FOR

NORTH CENTRAL ORANGE COUNTY...



AT 1117 PM PST...NATIONAL WEATHER SERVICE DOPPLER RADAR SHOWED 

ANOTHER LINE OF MODERATE RAINSHOWERS MOVING TOWARDS NORTHERN ORANGE 

COUNTY. THESE SHOWERS WERE LOCATED ALONG A LINE EXTENDING FROM 24 

MILES NORTH OF FREMONT CANYON TO 17 MILES NORTHWEST OF FREMONT 

CANYON TO 18 MILES WEST OF FREMONT CANYON...OR ALONG A LINE 

EXTENDING FROM SAN DIMAS TO ROWLAND HEIGHTS TO CYPRESS...MOVING EAST 

AT 20 MPH.



THUNDERSTORMS PRODUCING FLASH FLOODING WILL BE NEAR...

  9 MILES NORTHWEST OF FREMONT CANYON BY 1145 PM PST



HEAVY RUNOFF...MUD SLIDES AND THE THREAT OF FLASH FLOODING FROM RAIN 

THAT FELL EARLIER WILL CONTINUE UNTIL 1145 PM...AND AFFECT THE  

SIERRA FIRE AND YORBA LINDA FIRE BURNED AREAS AND AREAS DOWNSTREAM. 



ACCORDING TO THRESHOLDS PROVIDED BY THE U S GEOLOGICAL 

SERVICE...DEBRIS FLOWS ARE LIKELY IN THE FOLLOWING WATERSHEDS BURNED 

BY THE SIERRA FIRE... 



DRAINAGES IN FEATHERLY REGIONAL PARK...STREAM CROSSINGS ON STATE 

HIGHWAYS 91 AND 241 AND GYPSUM CANYON ROAD...AND SANTIAGO 

RESERVOIR..



AND DEBRIS FLOWS ARE ALSO LIKELY IN THE YORBA LINDA BURN AREA 

AREAS...INCLUDING PARTS OF TELEGRAPH CANYON ROAD AND CARBON CANYON 

ROAD.



RAINFALL THAT IS NORMALLY ABSORBED BY VEGETATION CAN RUN OFF ALMOST 

INSTANTLY. THIS CAUSES CREEKS AND DRAINAGE AREAS TO FLOOD MUCH 

SOONER DURING A STORM...AND WITH MORE WATER THAN IS NORMAL. 



THE SOILS IN A BURN SCAR ARE HIGHLY ERODIBLE SO FLOOD WATERS CAN 

CONTAIN SIGNIFICANT AMOUNTS OF ASH...MUD... BOULDERS...AND 

VEGETATION.  WITHIN THE BURNED AREA AND DOWNSTREAM... THE POWERFUL 

FORCE OF RUSHING WATER...SOIL...AND ROCK CAN DESTROY 

CULVERTS...BRIDGES...ROADWAYS...AND STRUCTURES...AND CAN CAUSE 

INJURY OR DEATH IF CARE IS NOT TAKEN.



RESIDENTS AND MOTORISTS IN AND BELOW RECENTLY BURNED AREAS SHOULD BE

ALERT TO HEAVY MUD AND DEBRIS FLOWS WHICH MAY BLOCK ROADS AND

CULVERTS. POTENTIALLY DANGEROUS FLOODING AND PROPERTY LOSS COULD

RESULT IN AREAS WHERE RUNOFF IS RESTRICTED OR BLOCKED.



LAT...LON 3394 11778 3392 11780 3385 11773 3381 11781

      3379 11784 3381 11777 3377 11772 3378 11766

      3381 11761 3389 11769



$$





RB

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