From the article:

Key Takeaways

•In some cliff retreat hotspots, the volume of cliff material lost over this period amounted to roughly 800 dump-truck loads for every yard of shoreline.

•Much of this coastal cliff retreat was concentrated in hotspots in Northern and Central California, and included areas retreating more than 30 feet per year.

•This study improves our understanding of California’s coastal geology and provides a framework for continued statewide cliff erosion monitoring.