1. Washington Statehood: On April 1, 1889, President Benjamin Harrison signed a legislation granting Washington Territory statehood, making it the 42nd state in the union.

2. Seattle Fire: On April 1, 1889, a small fire broke out in a cabinet shop in Seattle. Despite efforts to put out the fire, it quickly spread and destroyed 25 city blocks, causing over $20 million in damages. The fire led to the rebuilding of Seattle, transforming it into the modern city it is today.

3. Tacoma Narrows Bridge Collapse: On April 1, 1940, a new suspension bridge spanning the Tacoma Narrows collapsed after just five months of use due to a phenomenon known as "galloping gertie." The collapse led to major revisions in bridge engineering design and is studied to this day.

4. Mount St. Helens Eruption: On April 1, 1980, seismic activity began at Mount St. Helens, leading to a devastating eruption on May 18 of that year. This event was one of the deadliest volcanic eruptions in U.S. history, causing 57 deaths and over $1 billion in damages.

5. Women's Suffrage: On April 1, 1910, Washington became the fifth state to grant women the right to vote, eight years before the 19th Amendment was adopted nationally. Washington's early adoption of women's suffrage helped pave the way for the rest of the country to follow suit.