The unusually steep slopes and narrow slit of the canyon draining the Great Falls Basin just a few miles north of Trona stand out as a unique feature for the broader area that had me curious about its potential as a technical canyon for many years. Though this is an incredibly out-of-the-way location, I have managed to spend at least six of the second-weekend-in-Octobers of my life visiting the dusty and fragrant mining town of Trona for its (this year 77th) annual Gem-O-Rama event where world-class evaporite minerals can be collected. The event is always a great time and always impeccably organized but also leads to a similar experience year after year. I was craving the opportunity to do something new and skipping the morning "mud trip" seemed perfect. If all went well I'd be back in time for the afternoon "blow hole trip." I had no concern about doing the canyon alone other than if my car could get me to the start.
As I found out the canyon is actually rather stunning and is something I would be willing to do again (not something I say often). Certainly a regional wonder worthy of a detour or in conjunction with other local excursions. A short drive from the highway and a 40 min hike gives you over 2 hours of canyon. Excellent Alabama Hills-quality rock with flash flood polishing and sculpting reminiscent of some of the best Sierra canyons. Five beautiful and mostly unawkward drops. Nice moments of solitude. Only 100ft of rope needed so you do not need to carry too much gear.
A short five mile drive from the Trona Gem-O-Rama got me to the Great Falls turnoff. The road started alright at first but progressively the sand got deeper to the point that the auto-traction-control-whatever on my Prius began to slow me down and I had to delicately throttle to try to maintain enough speed to not come to a screeching sand burying halt. I made it 2.5 miles from the highway (0.5 miles short of the road end) until my car ground to a halt and refused forward progress. Fortunately the traction control seemed to behave somewhat different in reverse so I was able to back up and turn onto the slightly more compact wash surface adjacent to the road. The front of my car was stuck in sand above my mud flaps for some moments until I was able to carefully coax myself into a turn and then park on a slightly harder patch facing downhill. Getting out would be a problem for later! For now I felt lucky to have made it as close as I did. Wild burros watched my antics with mild curiosity, probably commenting among themselves about the inadequacies and stupidity of Prius driving city folks.
Prius-eating sand with the bottom of Great Falls in the distance
The approach hike was remarkably straightforward and so I made good time. There was a great trail leading up the side of the valley into a hanging valley. From here I could follow the contact between the two plutonic rocks (resistant Alabama Hills-style monzogranite and a more erosive granitic). For a portion of the approach I could not resist the lure of the slickrock and so veered slightly off. Somehow I managed to gain the 800 ft elevation to the saddle, though it felt like much less than that. The view from the saddle was great- a maze of granite rockpiles for miles ahead forming the Great Falls Basin proper. I picked my way down minor washes to the canyon bottom, then skirted just above the bottom to avoid the spring-fed vegetation thicket. A sandy jaunt and then some scrambling over and down boulder brought me to the first obvious rappel. The approach took me a pretty leisurely 45 minutes.
View from the saddle into Great Falls Basin
There were plenty of anchor options for this first 40ft rappel but it took a few moments of thought to decide what the best option would be to make the pull very easy. This was a comfortable rappel down a polished chute into a chockstone grotto below- a really nice start to the canyon. Wanting to get some decent photos despite the solo trip I did some silly selfie maneuvers (set up tripod, set 30sec timer, run and hoist myself up rope, look natural...).
Rappel 1, above and below
I was in it now. The entire canyon was in cool and comfortable shade which was a real treat. Chirpy birds abounded. It was all quite pleasant. A stemming downclimb led to more sandy floor, then another obvious rappel. I used the historic hardware left over from a water piping system for this short 25ft rappel.
Rappel 2
More sandy floored hallway and a nice cluster of trees led to a left turn in the canyon where things became more vertical. A downclimb around a concrete weir and then an awkward 8ft downclimb were next up. The bottom part of the downclimb was actually more of a foot slide down a pipe. Here the canyon became considerably more sculpted, the flash floods obviously carving strongly in this steeper, narrow place. There was also some nice reflected canyon golden light in this spot (frontispiece) too nice to resist more silly selfies.
Rappel 3
The third rappel from modern bolts and chains was a really pleasant 45ft drop. This canyon just kept getting better and at this point the walls towered steeply overhead. It was clear from the lack of footprints and fresh sedimentary features that this canyon flooded not all that long ago yet I was surprised at the lack of water. Only about 15 steps from the third rappel is the fourth at about 50ft length. I could see a very wet landing below so stripped down to shorts and put items in dry bags just in case. Previous accounts indicated this was often a swimming pool. This vertical rappel had a somewhat awkward start around then beneath a chockstone, then requiring careful avoidance of not snagging on piping and related metal shrapnel bolted to the rock. Once close to the bottom I could see the deep landing and so worked up momentum by kicking off the rock so I could pendulum over to the sand island and then drop onto it. This worked well but getting off the island to the shore required one ankle to be soaked. With care I was able to keep the rope mostly dry on the pull.
Rappel 4
Next up was a climb over a large boulder and then down the other side using an old pipe as a guide. The last rappel (40ft) was perhaps the most fluted and sculpted of them all. It was clear from the bathtub rings on the walls that this was often a swimmer as well- I appreciated the dry conditions given the cool comfort of the canyon. More tripod selfies of this photogenic spot, then a climb up the awkward chockstone at the downstream end of the basin.
Rappel 5, above and below
This darkest and narrowest corner then turned and opened into a wider boulder-bottomed canyon. I navigated over, down, between and around house to car sized boulders to bypass the last drop in the canyon before dropping onto the vast sandy floor of the wash. The size of the wash and amount of sandy fill attest to the ferocity of floods that must rip through this canyon. It makes me wonder how long the water pipe system actually managed to stay functional before it was abandoned. I was back to the car in three hours after I left it, pretty good time considering all the staged photos and little bit of anchor building I needed to do. The excitement was not over yet as I had to delicately boat my Prius out the soft sand and back to the highway. No incidents thankfully and in minutes I was able to rejoin the Gem-O-Rama festivities, thoroughly satisfied that I got the opportunity to get up to a nice little solo adventure. The rest of Gem-O-Rama was good fun with some of the best collecting I've ever done and some nice camping with UCR folks at the otherworldly Trona Pinnacles.
Thousands of years ago there was an earthquake that spectacularly shook the San Gabriel Mountains, causing the southeast face of its highest peak Mt San Antonio to detach and jumble its way downslope in a brief but terrifying instance of time. This landslide traveled at great speed (100 mph perhaps) down San Antonio Canyon, splashed up the east wall of the canyon as it rounded a bend, and decreased momentum to deposit person- to house-sized boulders on a sizable flat (Manker Flat). In a minute or two 50 million cubic meters of rock had traveled up to 2.5 miles away from where they started. This landslide has had effects on the landslide that still persist today- Manker Flat forms a sizable area of flattish ground where nearly a hundred cabins have been built; erosion into the higher parts of the landslide deposit have driven downcutting into a steep bedrock gorge, San Antonio Falls. As part of my mapping efforts in the area I was very interested to check out this canyon and document the amount of incision that has occurred. That it was supposed to be one of the highest quality bang for buck canyons in the San Gabriels (5 nice rappels for about 2 hours round trip) that I had not been to before would be an added bonus.
