Portland, OR Dike Break and Flood, May 1948
Within an hour the water was near the top of the Union avenue dike and the road was buckling and sagging. The road was closed by order of Sheriff Martin Pratt of Multnomah county. This sealed the last approach to Vancouver over the Interstate bridge.
The Denver dike break occurred about 9:15 p.m. at the Vanport underpass. Shortly after the Union avenue fill collapsed.
More than 100 men had labored all day to build a dike around rising water at the underpass turnaround, 500 feet north of where a culvert washed out at the entrance to the underpass. By nightfall engineers thought both places had been reinforced sufficiently to hold.
Gordon Black, 7239 N. Delaware avenue, was in charge of the underpass work group.
"I saw the water starting to stream out of the other side of the dike and yelled for everyone to get out of there," Black related.
"We ran as as fast as we could uphill to the top of the road."
Small Stream Becomes River
Within a matter of minutes the sandbag and earth dike gave away. What started as a small stream swelled to a river, then to a raging cataract.
While still shouting the alarm, Black and his workers saw large sections of the Denver sidewall earth give away.
As they watched, the current dragged one of Vanport's multiple dwelling units toward the underpass trestle. The house snapped off a tree and rammed into the trestle underpinnings, grinding them into splinters.
Then the house poked its way over the debris and tumbled over a 15-foot waterfall, turning end for end and smashing into matchwood.
Other houses were sucked into the opening and met similar fates. A few weathered the plunge and floated off toward Portland Meadows.
The breach widened quickly to about 500 feet and frequently several of the structures floated through abreast. They crashed over the falls with a tremendous groaning and wrenching of timbers. Clouds of dust from the old lumber filled the air.
At midnight the sheriff's office reported the Union avenue dike had been breached near the open air theater. This would soon fill the area behind the Faloma danger point. The Columbia Edgewater Golf club was in the line of the advancing flood.