

000 

WGUS76 KSGX 222042

FFSSGX



FLASH FLOOD STATEMENT

NATIONAL WEATHER SERVICE SAN DIEGO CA

140 PM PDT THU MAY 22 2008



CAC073-222130-

/O.CON.KSGX.FF.W.0025.000000T0000Z-080522T2130Z/

/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

SAN DIEGO CA-

140 PM PDT THU MAY 22 2008



...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 230 PM PDT FOR 

NORTH CENTRAL SAN DIEGO COUNTY...



AT 130 PM PDT...SHOWERS AND THUNDERSTORMS WITH HEAVY RAIN CONTINUED 

TO MOVE ACROSS NORTHERN SAN DIEGO COUNTY...INCLUDING THE AREAS THAT 

WERE BURNED BY THE POOMACHA...WITCH AND RICE FIRES. THUNDERSTORMS 

HAD HEAVY RAINFALL RATES IN EXCESS OF ONE INCH PER HOUR. THIS 

ACTIVITY WILL CONTINUE MOVING SOUTH AT 25 MPH.  

 

THE HEAVIEST RAIN AT 130 PM WAS NEAR THE WITCH CREEK AT SANTA YSABEL 

AND IN PORTIONS OF VALLEY CENTER. RAIN WAS STARTING TO TAPER OFF 

NEAR RAINBOW...FALLBROOK AND PALOMAR MOUNTAIN.



THROUGH 230 PM...THE SHOWERS AND THUNDERSTORMS WILL GRADUALLY SHIFT 

FURTHER SOUTH IN SAN DIEGO COUNTY.



IN ADDITION TO FLASH FLOODING...RAINFALL IS EXPECTED TO CAUSE DEBRIS 

FLOWS IN THE POOMACHA AND WITCH BURN AREAS ACCORDING TO THRESHOLDS 

PROVIDED BY THE USGS. AREAS AFFECTED INCLUDE VALLEY CENTER...

HIGHWAY 78 BETWEEN ESCONDIDO AND RAMONA...AND SANTA YSABEL. 



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. ADDITIONAL 

RAINFALL AMOUNTS OVER ONE INCH ARE POSSIBLE IN THE WARNED AREA.

  

THE WATERSHEDS BURNED THIS FALL ARE PARTICULARLY SUSCEPTIBLE TO FLASH

FLOODS AND DEBRIS FLOWS DURING RAINSTORMS. A SHORT PERIOD OF EVEN

MODERATE RAINFALL ON A BURNED WATERSHED CAN LEAD TO DEBRIS FLOWS.

RAINFALL THAT IS NORMALLY ABSORBED INTO HILLSLOPE SOILS CAN RUN OFF

ALMOST INSTANTLY AFTER VEGETATION HAS BEEN REMOVED BY WILDFIRE. THIS

CAUSES MUCH GREATER AND MORE RAPID RUNOFF THAN IS NORMAL FROM CREEKS

AND DRAINAGE AREAS. THE HIGHLY ERODIBLE SOILS IN A BURN SCAR ALLOW

FLOOD WATERS TO ENTRAIN LARGE AMOUNTS OF ASH, MUD...BOULDERS...AND

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

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

BRIDGES...ROADWAYS AND BUILDINGS...POTENTIALLY CAUSING INJURY OR

DEATH.



LAT...LON 3342 11682 3307 11664 3308 11700 3343 11732

TIME...MOT...LOC 2024Z 180DEG 0KT 3340 11708 3319 11704



$$



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