On May 30, 1948, a railroad berm on the edge of Smith Lake was breached and the city of Vanport — population 18,000 — was destroyed. The water level in the Columbia and Willamette Rivers had been high for weeks, but city officials told residents on the morning of the flood: "Dikes are safe at Vanport. You will be warned if necessary. You will have time to leave. Don't get excited." Many residents were unprepared for the flood that afternoon and left with only what they could throw into a suitcase in a matter of minutes. Fifteen people died in the flood.
Vanport had been quickly built in the early 1940s to provide temporary housing to employees working in ship building and ship repair at the Kaiser Company shipyards in Portland and Vancouver. At its peak, the population was around 42,000.
Before Vanport was built, Oregon was home to few African Americans —only 2,565 in 1940. But Vanport provided unprecedented job and housing opportunities for blacks. By the end of the war, 6,000 lived in Vanport alone, drawn from all over the country.
Former State Of Residence For African Americans Living In Vanport In 1945:
Source: First Annual Report of the Urban League of Portland, 1945
After WWII, Vanport's population decreased, but it also diversified as Japanese families relocated to the city after being interned during the war. When the flood destroyed the town, many of the racial minorities who had resided in Vanport moved to Portland, which until that point had had very few non-white residents.