US 34 Big Thompson Canyon

US 34 Re-Opened from Mile Points 72-74

US 34 has re-opened between mile points 72 and 74—just west of Waltonia—making it easier for canyon residents to travel to and from Estes Park during the permitted travel times. This two-mile stretch of the canyon has been closed so crews could dig up the highway and put in a layer of rock beneath the road surface so it better withstands the eroding effects of water in future floods.

US 34 Traffic Impacts

US 34 remains closed to through travel until late May 2018. Most of the roadway reconstruction will be finished prior to Memorial Day, but asphalt paving and milling operations will continue throughout the canyon in the summer of 2018 with minor and intermittent traffic impacts next summer. Project completion is scheduled for December 2018.  

Please keep in mind that lane closures are weather dependent and subject to change. Although the closure will be consistent, please continue to check this site for the most up to date information.

  • US 34 remains closed between mile points 72 and 80.
  • From Monday through Friday, expect a 500-foot rolling single-lane closure on US 34 between mile points (MP) 80 and 87 and between MP 80 and 83.
  • From Monday through Friday, expect a single-lane closure on US 34 between MP 67 and 68.
  • Please note that mile points 65 (Mall Road) to 71 (Rainbow Trout Lane) are open to public traffic.

Please call 970-667-1005 to schedule an appointment to get a permit for access during the closure.

  • You're allowed one permit per vehicle.
  • Permits provide through access on US 34 from MP 67 to MP 83 from 6-8:30 a.m., and from 4-7 p.m. throughout the closure.
  • Permit holders should plan for delays as pilot cars lead vehicles in both directions through the 13-mile work zone.
  • Crews are scheduled to work seven days a week to meet the aggressive schedule.
  • *Canyon residents are defined as those living along US 34 between Mall Road and the Dam Store along County Road 43 up to Glen Haven.
  • When the work zone is closed, the only vehicles permitted to travel through it are emergency service vehicles and, at specific times of the day, people who live in the canyon or are doing business in the canyon.
  • During snow events, drivers using the US 36 detour route between Lyons and Estes Park must follow any posted traction laws for passenger vehicles or chain laws for commercial vehicles.

US 34 - Damage

CDOT is looking to cut nearly two years off the expected permanent reconstruction on US 34 in the Big Thompson Canyon and, in the process, have little impact to travelers during the busy summer season. The tradeoff for this time savings is the current closure of the canyon through May 2018.

Flood Impact Analysis

US 34 Big Thompson Canyon was heavily damaged during the 2013 floods, with many homes damaged and over 100 air-lifted evacuations. The canyon and its residents also suffered from flooding in 1976. As a result of these two events, CDOT has been studying the hydraulic flow of the river in the canyon, and its impact on the road and bridges along its path. CDOT also is looking for safety improvements and resiliency solutions to prevent and protect against significant damage from future flood events.

Damage Overview

This section US 34 winds its way through the Big Thompson Canyon, providing major access between Loveland, Lyons, and Estes Park. During the flooding, watershed runoff combined with flows released from Lake Estes Dam and surges from debris dam breaches to produce huge flow surges that exceeded the 500–year flood event. The canyon section sustained widespread, massive damage. Major sections of roadway were washed away completely, along with access bridges and retaining walls. In the narrows, much of the roadway and grade were undermined, washing out the pavement from below and exposing the wall support structures.

Emergency (Temporary) Repairs

US 34 - Emergency Repairs
Temporary repairs were completed and the highway was reopened to traffic in both directions on Thursday, Nov. 11, 2013. CDOT and its contractors worked from both the east and west ends of the canyon to assess and repair the damage and restore local access as quickly as possible. Emergency repairs were extensive and included removing debris, re-establishing shoulders and embankments, replacing damaged asphalt, filling washed out sections with concrete fill, repairing local access structures, and repairing damaged drainage structures.

Permanent (Long-Term) Repairs

Permanent repairs will include removing and replacing much of the temporary asphalt, embankment fill, and temporary channel protection; as well as re-vegetating, replacing guardrails, and repairing fencing. Some of the roadway sections that were not destroyed, but experienced flood water overtopping the roadway, will be analyzed and possibly replaced.

See a brochure that further explains the permanent repair process.

Estimated Timeline

  • Est. Design Start: Summer 2014
  • Construction Start: 2016

Estimated Budget

  • $280 million


One of the goals in the repair process is to introduce certain betterments (improvements that go beyond bringing the roadway up to standard) to roadway facilities that were damaged and make them more resilient to similar storm events in the future. Having analyzed the damage caused during the flood event, certain design elements will be incorporated in an effort to prevent or lessen the severe damage that significant flood events can cause. During the permanent repair phase, several alternatives will be developed to ensure that the Big Thompson channel has increased capacity and the roadway has additional high water relief to handle large storm events.

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