Existing comment:
Impassable Barrier
In the 1920s this end of the canyon appeared to be a dead end, an impassable barrier to transportation. To highway engineers the
toughest challenge was the cliff above. Their solution: a one-mile tunnel behind the cliff face.
When tunnel and highway were completed in 1930, they opened the region to motor tourism, linking Zion to Bryce and the Grand
Canyon's North Rim. Now the tunnel itself has become kind of a barrier, as today's RVs and tour buses are too large for two-way
traffic within the tunnel. Expect short delays as oncoming traffic is held to allow oversize vehicles to pass through.
Work on the tunnel began with drilling small shafts into the north-facing cliff. Those shafts later became the tunnel's windows or
galleries, like the ones visible here. The four galleries are not the only source of light and air but were places to expel rubble as workmen tunneled toward both ends.
Portions of the tunnel were shored with timbers. In 1937 the entire tunnel was lined with concrete.
The temporary wooded framework as the east portal was replaced with a concrete bridge.
The small pilot tunnel was enlarged by drilling and blasting. Crews moved forward 30 to 36 feet a day. |