Back in September of 2007, I was moved to launch this blog with a post about an exposure of serpentine rock below a house being built up near the top of Crestmont Avenue. It looked like this at the time.

I called it “a nonstop disaster.” Maybe that was intemperate, but I also said it “will be repaired, shored up, repaved and regraded for the foreseeable future.”

Time for a welfare check.

I pass the spot every now and then and always give it a look, but don’t always photograph it. In 2015, eight years later, it looked like this.

All the crushed bits and surface dust had washed off, exposing the rock’s lovely color. And enough of the real rock had spalled off that a black wire fence had been added above the little wooden fence, though not tied to it. I also thought at the time that the roadway beneath the exposure was buckling a little.

And here it is in early November 2026, nineteen years later.

By now, most of the original surface has crumbled off; also, that little wooden fence has been patched and bolstered. The wire fence has an extra set of gray steel poles holding it back, and fallen rock has pushed through the gap between the fences, like a belly bulging between shirt and shorts. The roadway has been resurfaced, but I didn’t check to see whether it underwent more work than that.

The future promises more of the same steady decay. Meanwhile the rock itself is gorgeous, if you’re into rocks.

Serpentinite — the official name of serpentine rock — is not highly regarded by engineering geologists. It’s full of fractures and tends to crumble, but with due care it can be built upon. There are houses next door that are set into this same hillside, and presumably the people who planned them did suitable strength tests and specified sufficient concrete to seal the rock off from sun, rain and gravity. They’re the professionals and I’m an unlicensed amateur.

If I’m still around, look for an update in a decade or so.

This entry was posted on 9 November 2026 at 8:01 am and is filed under Oakland serpentinite. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.