Walking the Cliffs at Devil's Slide
I already wrote a bit about our visit to Devil's Slide on Saturday. Here's more detail- with pictures- about our hike, the old Highway 1, and why traffic now flows through a tunnel.
California's Highway 1, called in some places the Pacific Coast Highway, was an ambitious public engineering feat completed in the 1930s. It traversed rugged terrain to connect cities and towns on the coast. It was not only utilitarian but jaw-droppingly beautiful. Highway 1 is widely cited as one of the top scenic drives in the US.
Devil's Slide, about 10 miles of San Francisco, is one of many stretches of Highway 1 where the road hugs the coastal mountainside. From the shoulder of the road it's 200' or more down to the pounding surf of the Pacific Ocean below.
In this picture (above) you can see the original route of Highway 1 as it was completed in 1936. The road edges around the flank of San Pedro Mountain.
...Well, not the original route. The road was rebuilt in 1940 after a major landslide wiped out a lot of this section. Landslides happened several more times after that. My recollection from living in the SF Bay Area in the 1990s and 2000s was that every rainy season here was at least one alert on the radio, "Highway 1 is closed at Devil's Slide...." Some of these minor closures to clean up debris on the roadway. Other closures lasted days or weeks to dig out the road and shore up its foundation.
Why landslides here?
Landslides happen frequently at Devil's Slide- and hence its name- because San Pedro Mountain has a lot of sandstone as its top layers. You can see the layers of sandstone in the second picture, above. Sandstone erodes easily, so the action of waves and wind and rain eat away at it. Other mountains in the area are made of granite and don't have this weakness.
As early as the 1950s local activists advocated for rerouting Highway 1 through a tunnel under the San Pedro Mountain. This was deemed more feasible than routing over the mountain due to its steepness and environmental sensitivity. The state and county finally agreed in the 1990s, and in 2005 construction of twin tunnels, 1.2km long, began. When the tunnels opened in 2013 a 1.3 mile stretch of the old road was blocked off to vehicle traffic and made a hiking/biking trail. There are small parking lots at each end. The south end even has a bus stop.
As glorious a driving route as Highway 1 is, the Devil's Slide area is even better as a hiking/biking route.
Update: keep reading about Devil's Slide with part 2: Birds and Battlements!
[This entry was cross-posted from https://canyonwalker.dreamwidth.org/186644.html. Please comment there using OpenID. That's where most of the action is!]
California's Highway 1, called in some places the Pacific Coast Highway, was an ambitious public engineering feat completed in the 1930s. It traversed rugged terrain to connect cities and towns on the coast. It was not only utilitarian but jaw-droppingly beautiful. Highway 1 is widely cited as one of the top scenic drives in the US.
Devil's Slide, about 10 miles of San Francisco, is one of many stretches of Highway 1 where the road hugs the coastal mountainside. From the shoulder of the road it's 200' or more down to the pounding surf of the Pacific Ocean below.
In this picture (above) you can see the original route of Highway 1 as it was completed in 1936. The road edges around the flank of San Pedro Mountain.
...Well, not the original route. The road was rebuilt in 1940 after a major landslide wiped out a lot of this section. Landslides happened several more times after that. My recollection from living in the SF Bay Area in the 1990s and 2000s was that every rainy season here was at least one alert on the radio, "Highway 1 is closed at Devil's Slide...." Some of these minor closures to clean up debris on the roadway. Other closures lasted days or weeks to dig out the road and shore up its foundation.
Why landslides here?
Landslides happen frequently at Devil's Slide- and hence its name- because San Pedro Mountain has a lot of sandstone as its top layers. You can see the layers of sandstone in the second picture, above. Sandstone erodes easily, so the action of waves and wind and rain eat away at it. Other mountains in the area are made of granite and don't have this weakness.
As early as the 1950s local activists advocated for rerouting Highway 1 through a tunnel under the San Pedro Mountain. This was deemed more feasible than routing over the mountain due to its steepness and environmental sensitivity. The state and county finally agreed in the 1990s, and in 2005 construction of twin tunnels, 1.2km long, began. When the tunnels opened in 2013 a 1.3 mile stretch of the old road was blocked off to vehicle traffic and made a hiking/biking trail. There are small parking lots at each end. The south end even has a bus stop.
As glorious a driving route as Highway 1 is, the Devil's Slide area is even better as a hiking/biking route.
Update: keep reading about Devil's Slide with part 2: Birds and Battlements!
[This entry was cross-posted from https://canyonwalker.dreamwidth.org/186644.html. Please comment there using OpenID. That's where most of the action is!]