This is useful information for anyone planning a trip along this part of the towpath this spring...

From NPS website:

C&O Canal Towpath Closure at Paw Paw Tunnel

Date: February 15, 2017
Contact: Matt Graves, Supervisory Park Ranger, 240-625-2931

Oldtown, MD - The Chesapeake and Ohio Canal National Historical Park (C&O Canal) will be performing a rock scaling project along the towpath at the northern or downstream portal of the Paw Paw Tunnel (Mile 155.2) starting early April 2017. Rock scaling is the physical removal of loose rock and unstable surface materials that pose a hazard. A portion of the towpath and boardwalk will be closed to visitors during the project. Visitors should also expect short intermittent closures and delays from the parking lot to the Paw Paw Tunnel entrance during the work.

The project will enhance visitor safety by reducing the risk of injury from falling rocks. The rock formation through which the canal and towpath cuts through, north and downstream of the tunnel, has a history of rock layers shearing off and falling on the towpath. This rock formation composed of shale is called “slickenslide” and is common to this area.

To provide thru-access for bicylists during the project, a bypass trail will be opened using an old logging road on the berm side of the Canal upstream of the south tunnel portal. A temporary “bridge” will be installed across the Canal prism that connects with an abandoned logging road that provides a gentler grade to the top of Tunnel Hill. This temporary by-pass then connects with the existing Tunnel Hill Trail. The existing Tunnel Hill Trail will remain open during the project, but for safety reasons, cyclists will be required to dismount and walk their bikes across the mountain using the bypass trail detour. The bypass will be clearly marked with signs.

The existing Tunnel Hill Trail will remain open to hikers approaching from the south or upstream. Visitors should be aware that the trail is steep and strenuous. Park visitors may still walk through the tunnel to the northern portal to experience the tunnel. The park anticipates the project to last 120 - 150 days with completion and full re-opening in late July 2017. Completion of this project may be impacted by weather conditions.

To facilitate the work, construction equipment staging will require closing a section of the Paw Paw Tunnel picnic area parking lot. Additionally, temporary delays on the towpath approaching the south portal should be expected as work crews and equipment move to/from the work site. Work crews will use the tunnel to gain access to the site.