Red Mountain Pass reopened about 4:10 p.m. after being closed midafternoon Monday because a semitrailer jack-knifed.

“The chain law went into effect at 2:42 p.m., and at 3:23 p.m., the unchained semi jack-knifed and closed both directions at mile post 81.5,” said Nancy Shanks, spokeswoman for the Colorado Department of Transportation.

The semi was headed south when it jack-knifed on the northern side of the pass, Shanks said. It blocked both lanes of traffic.

The driver was cited by the Colorado State Patrol. Another driver who spun out and blocked the southbound lane for about an hour was also cited for being unchained.

“We like the message to go out to see those chain laws followed,” Shanks said, “for everyone’s safety.”

All commercial vehicles must have chains and passenger vehicles are required to have snow tires or four-wheel drive for current driving conditions on the pass.

abutler@durangoherald.com