About 100 million years ago, in the late Mesozoic Era, the Okanogan terrane (microcontinent) docks against the North American continent. This collision adds to the land mass of North America and exten...
About 16,900 years ago, the Vashon glacier begins to melt and recede from lands that will come to be known as the Puget Sound region and the Columbia Basin region. By 15,000 years ago, the glacier has...
Beginning about 14,900 years ago, salmon begin to colonize Puget Sound. During the last ice age, when a 3,000-foot-thick glacier moved out of Canada and traveled as far south as Olympia, no salmon, or...
Beginning about 7,000 years ago, the climate become more like the modern era, relatively wetter and cooler than in the previous 3,000 years. With this change the ecosystems of the Puget lowland began ...
Approximately 5,600 years ago, a massive landslide removes .7 cubic miles of earth from the summit of Mount Rainier. The ensuing mudflow, which spreads as far as modern-day Kent, is called the Osceola...
In about 1450, an immense landslide tumbles off Table Mountain in Skamania County and completely blocks the Columbia River, shoving it a mile off course. A lake forms behind the dam extending as far a...
In April 1596, English merchant Michael Lok and Apostolos Valerianos, a Greek pilot and mariner, meet in Venice to discuss a voyage that Valerianos had taken in 1592. The mariner, who was better known...
On January 26, 1700, at about 9:00 p.m. Pacific Standard Time a gigantic earthquake occurs 60 to 70 miles off the Pacific Northwest coast. The quake violently shakes the ground for three to five minut...
In the early 1700s, European horses arrive on the Columbian plateau, having moved north through tribal trade networks from Pueblo villages located in present-day New Mexico. The Plateau tribes, who fo...
In about 1725, Clatsops discover shipwrecked sailors whom they call Tlehonnipts (those who drift ashore) on a beach near Satsop Spit, which was located on the southern (Oregon) side of the mouth of th...
On August 11, 1774, Spanish explorers on the ship Santiago, commanded by Juan Perez, sail past the future state of Washington, sight the peak that will later be named Mount Olympus, and name it "Cerro...
On July 12, 1775, Bruno de Hezeta, Juan Perez, and others from the Spanish ship Santiago land on the shore of a wide bay and claim Nueva Galicia (the Pacific Northwest) for Spain. This is the first Eu...