

000 

WGUS76 KSGX 222201

FFSSGX



FLASH FLOOD STATEMENT

NATIONAL WEATHER SERVICE SAN DIEGO CA

255 PM PDT THU MAY 22 2008



CAC073-222315-

/O.CON.KSGX.FF.W.0027.000000T0000Z-080522T2315Z/

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

SAN DIEGO CA-

255 PM PDT THU MAY 22 2008



...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 415 PM PDT FOR

CENTRAL SAN DIEGO COUNTY...



AT 250 PM PDT...SHOWERS AND SCATTERED THUNDERSTORMS WITH LOCALLY 

HEAVY RAIN WERE MOVING ACROSS THE CENTRAL SAN DIEGO COUNTY INLAND 

VALLEYS...FOOTHILLS AND MOUNTAINS...INCLUDING THE AREAS THAT WERE 

BURNED BY THE WITCH AND ANGEL FIRES. 



THE HEAVIEST RAIN AT 250 PM WAS FROM RAMONA AND SAN DIEGO COUNTRY 

ESTATES TO NEAR DESCANSO...WITH LOCAL RAINFALL RATES OF ONE HALF 

INCH PER HOUR. THE ACTIVITY WAS SLOWLY DECREASING AND WILL CONTINUE 

MOVING SOUTHEAST AT 25 MPH. RAIN HAD TAPERED OFF IN THE NORTH COUNTY 

TO THE NORTH OF VALLEY CENTER AND LAKE HENSHAW.



THROUGH 400 PM...SHOWERS AND ISOLATED THUNDERSTORMS WILL GRADUALLY 

DECREASE AND SHIFT FURTHER SOUTH IN SAN DIEGO COUNTY.



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

FLOWS IN THE WITCH BURN AREA ACCORDING TO THRESHOLDS PROVIDED BY THE 

USGS. AREAS AFFECTED INCLUDE SANTA YSABEL...RAMONA...AND HIGHWAY 78 

BETWEEN ESCONDIDO AND RAMONA.



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 3337 11683 3308 11656 3285 11640 3276 11651 

      3288 11677 3289 11684 3297 11701 3321 11715

TIME...MOT...LOC 2142Z 180DEG 0KT 3317 11691



$$



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