Special Weather Statement - Increased Landside Risk...

posted Jan 21, 2011, 9:44 AM by smike@guemesfire.org
447 AM PST FRI JAN 21 2011...

RAINFALL AMOUNTS OF ABOUT A QUARTER TO AN INCH FELL DURING THE
PAST 24 HOURS...ENDING AT 4 AM PST THIS MORNING...ON TOP OF
ALREADY SATURATED SOILS. ANOTHER TENTH TO A HALF INCH OF RAIN
IS EXPECTED TODAY...WITH LOCALLY HIGHER AMOUNTS IN THE MOUNTAINS.
THIS AMOUNT OF RAIN WILL ONLY SERVE TO PUT EXTRA PRESSURE ON SOIL
INSTABILITY...LEADING TO AN INCREASED RISK OF LANDSLIDES. THERE
HAVE BEEN LANDSLIDES IN WESTERN WASHINGTON DURING THE PAST WEEK.

WHILE THE USGS RAINFALL THRESHOLDS WERE DESIGNED FOR THE SEATTLE
AREA OF THE PUGET SOUND...MOST OF THE LOWLANDS OF WESTERN WASHINGTON
ARE SIMILARLY SUSCEPTIBLE TO LANDSLIDES CAUSED BY WET SOILS. AREAS
MOST SUSCEPTIBLE TO LANDSLIDES UNDER THESE CONDITIONS ARE STEEP
COASTAL BLUFFS AND OTHER STEEP HILLSIDES.
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