After a mud slide at its Beacon Hill end in 1917, the wooden superstructure of the 12th Avenue Bridge over the Dearborn Cut was removed and the bridge assumed its contemporary elevation. Here, both views look south along the same line and level, although in the older scene the deck is still paved with planks.

PAUL DORPAT

After Beacon Hill was clearcut in 1881, the clay-based knoll that distinguished it south of Dearborn was exposed to the elements, and pieces began to slip away. The original steel bridge on 12th Avenue featured a wooden superstructure that climbed to the knoll. After heavy rains in the spring of 1917, the approaches collapsed as a chunk of the hill caved in, bowing the bridge and moving it about 30 inches north.

This scene, dated Oct. 24, 1917, reveals a steel bridge cleared of its wooden crown. After a jog at the bridge's south end, 12th Avenue is being cut through part of the knoll. Until the new grade was ready to have tracks for the Union Trunk Line's electric trolley, passengers dismounted the trolley at the south end of the bridge. From there they climbed the stairway, here right of the bridge, and boarded a second trolley above on the old grade of 12th Avenue. Both trolleys are seen here - one on the bridge, one on the horizon to the right of the power poles.

In 1923 more of the north face of Beacon Hill was sluiced away, this time deliberately, with water canons. The most recent adjustment along the Dearborn Cut came when Interstate 5's celebrated "ramps to nowhere" were connected to Interstate 90 along the southern slope of the cut. This fulfilled the original justification for moving the 1.25 million cubic yards of earth that made the Dearborn Cut. In 1909 when the cutting began, the ridge was considered an inhibitor to connecting downtown Seattle with Spokane along easy grades.

Paul Dorpat specializes in historical photography and has published several books on early Seattle.