|A very strange-looking sandbar at Big Lagoon in Humboldt Lagoons State Park on California's north coast.|
But when that geologist walks ONTO a bar, she just gets sand on her feet.
Yeah, yeah, I know, shut up and stick with the science...
We're traveling north on a journey through the Cascadia Subduction Zone, exploring this unique region with an eye to the geology, and the beauty, of the region. We've explored the Redwood forests of the Eel River, and the Lost Coast where the Cascadia zone begins. Today we are looking at a unique state park along the coast north of Eureka, California, and south of Crescent City. It's called the Humboldt Lagoons State Park, and the three lagoons found there are bounded by stunning examples of baymouth bars.
|Big Lagoon at Humboldt Lagoons State Park (source: Google Earth)|
|Big Lagoon at Humboldt Lagoons State Park|
Intense rainfall sends sediments down the many rivers and streams, and vast amounts are added to the coastal waters. When waves encounter the coast at an angle, the swash and backwash of the water causes sediment to be transported along the coast, a process called longshore drift. There is a tremendous amount of sediment in this coastal system.
|Humboldt Lagoon also include a county park at the south end of Big Lagoon. It's a nice place to see coastal erosion!|
In most bays along the Cascadia coast, rivers are large enough to keep the bays open, but at Humboldt Lagoons only small streams are present. Water can simply seep through the sandbar rather than flowing out. The bays are breached only during the wettest, most intense storms. The baymouth bars are miles long, and incredibly straight (see the Google Earth image above). They don't look natural, and yet they are.
|Smaller Stone Lagoon is just north of Big Lagoon.|
The next stop on our vagabonding tour of the Cascadia Subduction Zone is Crescent City at the far north end of California. We'll have some things to learn about tsunamis in California.