Shallow roots and bare soil make hills vulnerable to landslides.

Unsound grazing management allowed shallow-rooted annuals to replace deep-rooted native perennials on virtually all of California's grasslands. Landslides are now a problem statewide. Slumps (sunken areas) at left and center right are small landslides. Near San Juan Bautista, south of San Francisco Bay, U.S.A.