

000 

WGUS76 KSGX 180655

FFSSGX



FLASH FLOOD STATEMENT

NATIONAL WEATHER SERVICE SAN DIEGO CA

1050 PM PST FRI FEB 17 2006



CAC059-180745-

ORANGE CA-

1050 PM PST FRI FEB 17 2006



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

NORTH CENTRAL ORANGE COUNTY...



AT 1039 PM PST...THE THUNDERSTORMS THAT WERE RESPONSIBLE FOR 

PRODUCING FLASH FLOODING WERE LOCATED ALONG A LINE EXTENDING FROM 8 

MILES EAST OF FREMONT CANYON TO 7 MILES SOUTHEAST OF FREMONT CANYON 

TO 7 MILES SOUTH OF FREMONT CANYON...OR ALONG A LINE EXTENDING FROM 

CORONA TO 8 MILES SOUTH OF CORONA TO 6 MILES NORTH OF MISSION 

VIEJO...MOVING EAST AT 10 MPH.



HEAVY RAIN HAS ENDED OVER THE SIERRA FIRE AND YORBA LINDA FIRE 

BURNED AREA...HOWEVER HEAVY RUNOFF...MUD SLIDES AND THE THREAT OF 

FLASH FLOODING WILL CONTINUE UNTIL 1145 PM...AND AFFECT 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 THE YORBA LINDA AND 

SIERRA FIRE 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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