Puget Sound, the area of water which runs between the Washington Coast and the Pacific Ocean around Seattle is a beautiful collection of channels, branches, inlets and islands.
Known in native Lushootseed as “Whulge”, which means “salt water”, the Sound is made up of a complex estuary system of marine waterways and basins, fed by significant seasonal meltwater from the Olympic and Cascade drainage basins.
Viewing Puget Sound from the air gives some clues to its origin: its coastline is very complex with many finger-like bays and inlets stretching inland from the sea.
This is because the Sound is a flooded river system, also known as a fjord, similar to those seen along the Scandinavian coastline.
Puget Sound was created by the repeated advance and retreat of large continental ice sheets over millions of years, which scoured away the surface of the land but also left behind a range of deposits as they retreated and melted.
Lake Washington and Lake Sammamish (both known as ribbon lakes due to their long, thin shapes), the Hood Canal and the main Puget Sound basin were all carved out by these powerful glacial forces.
The deposits left as the glaciers subsequently retreated can be seen as silty, thick layers known as glacial till, as jagged isolated boulders or even in more organised mounds such as the drumlin fields of hundreds of hill-like structures seen around the coast.
The last glacial retreat was 11,000 years ago, which also caused surrounding sea levels to rise as the ice melted and resulted in the deep waters and flooded valleys of the Puget Sound system.
The first European to explore Puget Sound was George Vancouver in 1792, who named the area after Peter Puget, one of the Lieutenants on his expedition.
Puget Sound is now also connected to the freshwater of Lake Washington by the Lake Washington Ship Canal, a man-made waterway to link the estuary with the dock and naval shipyard in the nearby lake.