DENVER (KDVR) — Interstate 70 was closed at Floyd Hill Thursday afternoon because of loose rocks after blasting above the highway.

The rock is above the highway between U.S. 6 and County Road 65, according to Colorado State Patrol, which posted about the closure at 3:12 p.m. U.S. 40 was open.

The westbound lanes reopened just before 4:40 p.m. Eastbound I-70 reopened a few minutes later.

Aerial image of traffic backed up on a snaking Interstate 70
Traffic backed up on Interstate 70 because of a closure at Floyd Hill (KDVR)

Delays were already expected on this stretch of I-70 because of ongoing construction work for the Floyd Hill expansion project. This month, crews are rock scaling and blasting along the route.

CDOT said Thursday that rock blasting is the reason for the loose rocks that caused the closure.

I-70 Floyd Hill construction underway

Rendering of the completed I-70 Floyd Hill project’s Central Section looking south
A rendering of the completed I-70 Floyd Hill expansion project’s Central Section looking south. Crews are getting the stretch of interstate ready for the major construction project expected to last for the next several years. (Credit: Colorado Department of Transportation)

The rock-scaling work this month “will allow crews to widen eastbound I-70 to build an extended on-ramp from the U.S. 6 interchange to the top of Floyd Hill,” according to CDOT.

The $700 million I-70 Floyd Hill expansion project will add a westbound express lane from west of Evergreen to eastern Idaho Springs and add improved traffic flow and safety features. The 8-mile stretch is notorious for backups and crashes.

Construction began in July and is expected to continue into late 2028.