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<br />
<br />2021 Multijurisdictional Local Hazard Mitigation Plan
<br />
<br />
<br />
<br />Date
<br />
<br />
<br />Event Type
<br />FEMA
<br />Declaration
<br />Number
<br />
<br />
<br />Location
<br />February 1995 Late Winter Storms (Severe Winter Storms,
<br />Flood, Landslide, Mudflows)
<br />1046-DR-
<br />CA
<br />San Mateo County
<br />Impacts: All California counties except Del Norte were included in this declaration.
<br />December 28, 1996 – April 1, 1997 Severe Storms, Flooding, Mud, and Landslides DR-1155 San Mateo County
<br />Impacts: Not reported
<br />February 1998 Landslides N/A San Mateo County
<br />Impacts: The main slide in La Honda began moving continuously by February 11 and accelerated after a period of rain. Three houses at
<br />the head of the slide were red tagged, as were five other houses on or near it. San Mateo County drilled three wells in a road
<br />crossing the slide and began pumping wells. The County also dug plastic-lined trenches to facilitate drainage. Seven homes on
<br />Esplanade Drive in Pacifica were evacuated after a 30-foot cliff retreated 10 feet to the rear edge of the homes.
<br />February 2, 1998 El Niño (Flood and Landslides) DR-1203 San Mateo County (Various
<br />Cities)
<br />Impacts: San Mateo County recorded $55 million in damage to public and private properties. La Honda, Moss Beach, Pacifica, Daly
<br />City, and Portola Valley listed $38 million in damage. Hundreds of hillsides failed. The pre-existing Polhemus landslide (earth
<br />slump) reactivated. Shoreline retreat occurred in Daly City, Pacifica, Tunitas Creek, and Moss Beach.
<br />Dec. 17, 2005 – Jan. 12, 2006 Winter Storms (Severe Storms, Flood,
<br />Mudslides, Landslides)
<br />DR-1628 San Mateo County
<br />Impacts: Damage estimates for the region exceeded $100 million. Three homes were nearly wiped out by mudslides.
<br />March 29 – April 1, 2006 Spring Storms (Severe Storms, Flood,
<br />Landslides, Mudslides)
<br />DR-1646 San Mateo County
<br />Impacts: Damage not available.
<br />April 1, 2006 Debris Flow N/A San Francisco Peninsula Coast
<br />Impacts: The hardest hit areas were water-soaked hillsides in Brisbane, Broadmoor, and El Granada. In total, 83 damage sites were
<br />documented throughout San Mateo County. A slide caused Highway 1 at Devil’s Slide to be closed for several months.
<br />April 4, 2006 Debris Flow N/A Santa Cruz Mountains (Zone)
<br />Impacts: Heavy and persistent rains in the Santa Cruz mountains during the first half of April caused many landslides. Damage was
<br />estimated at nearly $13 million, with at least $6 million charged to county road damage.
<br />April 22, 2006 Landslide N/A Half Moon Bay
<br />Impacts: Landslide downed fiber optic phone lines, leading to phone service outages in several San Mateo County coastal cities.
<br />December 6, 2014 Landslide N/A CA-84 East, between Old La
<br />Honda Rd., and Highway
<br />35/Skyline Blvd.
<br />Impacts: A landslide led to a traffic alert for motorists on CA-84 East, where only one lane was open for traffic.
<br />January 18 – 23, 2017 Severe Winter Storms, Flooding, and Mudslides DR-4305 San Mateo County
<br />Impacts: Not reported
<br />February 1 – 23, 2017 Severe Winter Storms, Flooding, and Mudslides DR-4308 San Mateo County
<br />Impacts: Not reported
<br />Sources: ABAG Local Hazard Mitigation Plan 2012, San Mateo County Sheriff 2015, USGS 1998, SFGate 2006, CBS Local 2014, NOAA
<br />Severe Storms Database 2016, ABC News 2009, NBC News 2016, KRON 4 2016
<br />
<br />Sites of Repeated Landslides
<br />In addition to the one-time events listed in Table 12-1, the following ongoing problem areas have been reported:
<br /> The southwestern portion of the County has experienced repeated damage from debris flows, including
<br />the Tunitas Creek, San Gregorio, and Pescadero watersheds. Debris flows are widespread on the natural
<br />
<br />
<br />
<br />12-4
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