Traffic through Oregon City was disrupted Tuesday morning after a rockslide forced the closure of the Highway 99E tunnel, creating delays along one of the primary routes connecting communities south of Portland. Transportation officials shut down the corridor after debris fell near the entrance to the tunnel, raising concerns about additional rockfall and the stability of the surrounding hillside.
The incident occurred early Tuesday when rocks and loose material were discovered blocking portions of the roadway near the tunnel entrance. Crews from the Oregon Department of Transportation quickly responded to the scene and closed the highway in both directions as a precaution. The debris itself could be cleared relatively quickly, but the greater concern involved the rock face above the highway, where unstable formations could continue to break loose.
Highway 99E runs along a narrow stretch of terrain carved through steep hillsides near the Willamette River in Oregon City. Portions of the roadway pass directly beneath exposed rock and through short tunnels constructed to accommodate the terrain. These conditions make the route particularly vulnerable to rockfall events, especially during seasons when moisture and temperature changes weaken natural rock formations.
Transportation engineers spent Tuesday evaluating the hillside above the tunnel to determine whether additional rocks were at risk of falling. In situations like this, crews often perform scaling work to remove loose debris from the rock face before allowing traffic to resume. Additional safety measures may also be required depending on the results of the inspection.
The closure temporarily halted traffic along a key commuter and freight corridor used by thousands of drivers traveling between Clackamas County and the Portland metropolitan area. Drivers were diverted onto nearby surface streets and alternate highways, which quickly became congested during peak morning travel hours.
By Wednesday morning, the situation remained under close monitoring as crews continued to assess the stability of the hillside. Transportation officials must confirm that the rock face is secure before reopening the route to normal traffic. While debris removal is often straightforward, ensuring the long-term safety of the roadway can take additional time depending on geological conditions.
For travelers coming from southern Oregon, the closure is unlikely to affect most long-distance routes heading toward Portland or the northern Willamette Valley. Interstate 5 remains the primary north south corridor through the state and was not impacted by the slide. Drivers traveling from communities such as Grants Pass, Medford, and Roseburg can still reach the Portland area using Interstate 5 without interruption.
However, those planning to enter Oregon City directly or travel along Highway 99E through Clackamas County may encounter detours or minor delays if the tunnel remains closed while inspections continue. Local traffic in the Oregon City area experienced the greatest disruption Tuesday as drivers navigated alternative routes around the blocked section of highway.
Rockslides are a recurring challenge along several Oregon highways that run through steep or mountainous terrain. Natural erosion, rainfall, and seasonal weather patterns can loosen rock formations over time, occasionally sending debris onto roadways without warning.
Transportation officials continue to monitor the site and will reopen the Highway 99E tunnel once engineers determine that the surrounding rock face is stable and safe for travel. Until then, drivers heading into Oregon City are encouraged to plan alternate routes and allow extra time for travel.