Beach Formation in California coast Beaches are dynamic landforms altered by wind and waves in a continual process of creation and erosion. Seasonal cycles of sand deposition and loss dramatically affect the appearance of beaches from summer to winter. Wide and gently sloping in summer, they become steep-fronted and narrow in winter, and cam vanish overnight, stripped of sand by violent storm waves. Most of the sand removed from winter beaches is deposited in offshore sandbars and is returned to the beach during the mild summer months by gentl ....