SAN FRANCISCO (KCBS) – Calling it the first step in estimating potential losses from a major winter storm, the California Geological Survey has released its most detailed statewide map on landslide susceptibility, and the map labels several parts of the Bay Area as high hazard.

KCBS’ Anna Duckworth Reports:

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The map, which identifies high risk areas with bright colors, takes degree of slope, strength of rock and population density into account.

Geologist Chris Wills said many of the hilly and mountainous areas of the state are considered highly susceptible because of construction that happened early last century before grading codes were enforced.

“There are a number of areas in the Bay Area and Los Angeles where you have this convergence of a very high population and a high susceptibility to landslides, which means development in areas that are prone to landslides,” said Wills.

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Wills said the Santa Cruz Mountains are a notably high hazard area, as are parts of Contra Costa, Alameda and Santa Clara Counties, and because they’re so steep, parts of Marin.

“As you go farther north into northern Sonoma County and up the coast, there is high susceptibility all the way up the coast,” said Wills.

Wills said the map is meant to be an overview for California’s emergency planners, so they know which areas to be aware of when it comes to big winter storms.

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