Geography
How Sandspits and Tombolos Attach Islands to Mainland Shores
Quick fact
A steady supply of sand and a specific wave angle can build a sandspit across a strait in just a few decades, permanently connecting an island to the mainland—a process that has reshaped coastlines and even influenced human settlement.
Why this is interesting
Have you ever wondered how some islands are literally tied to the mainland by a narrow ribbon of sand? That ribbon is a tombolo, and it forms through a fascinating dance of waves and sediment.