Cool weather, light winds, picturesque clouds, and Dales-green hills… If running in Upper Las Virgenes Canyon Open Space Preserve (Ahmanson Ranch) could always be like this.
Here are a few more photos from the run.
Some related posts:
– After the Kenneth Fire: The Theme is Green
– Upper Las Virgenes Canyon Open Space Preserve (Ahmanson Ranch) After the 2025 Kenneth Fire
As I worked up the Old Boney Trail, I looked for anything blooming. The empty seed pods from last year’s bigpod Ceanothus bloom were still present on many plants, but not a flower was in sight.
Lack of rain will do that. Although today’s run was after Southern California finally received some rain, the first few months of the rain season had been ridiculously dry. From July 1, 2024, to January 24,2025, Downtown Los Angeles recorded only 0.16 inch of rain — tying 1962-1963 for the driest start to the Rain Year on record.
Over the 20+ miles of trail that I would run today, the only conspicuous wildflower was this purple nightshade along the Old Boney Trail. Ceanothus, paintbrush, milkmaids, phlox, poppy, and other early-blooming species might be seen in normal or wet years.
Very early in the run, I came across some disturbing tracks on the Old Boney Trail. I first saw them on Danielson Road, and they continued on Old Boney all the way to Blue Canyon. From the tracks, I could see they powered directly up the hills and sped through the straightaways.
Usually, when I do the long climb out of Upper Sycamore on the Old Boney Trail, it’s to do the Western Ridge (Mountaineer’s Route) on Boney Mountain. This morning, the combination of crags, clouds, and early morning light on Boney Mountain looked especially inviting. I almost turned up the use trail that ascends the ridge. Resisting the impulse, I continued on the Old Boney Trail — past the Fossil, Blue Canyon, and Chamberlain Trails — to the Serrano Valley Trail and Serrano Valley.
It had been over a year since I’d been to Serrano Valley. It is one of the prettiest spots in the Santa Monica Mountains. It has a “big sky” feel that I always enjoy. When combined with a run down Serrano Canyon, the experience is exceptional.
One of the interesting things to see in Serrano Canyon is a large landslide scar on the north side of the canyon, about a half-mile from Sycamore Canyon. The trail goes over the foot of the slide. Some boulders near the trail contain fossils, similar to those found on the Fossil Trail.
As the landslide scar came into view, something had changed — there was a “new” rockslide in the middle of the old landslide scar. When I stopped to take a photo, I could hear rocks and debris trickling down the slope. This suggested the slide was still active and might be very recent. When did it happen?
The last time I’d photographed the landslide scar was in February 2022. At that time, this new rockslide hadn’t occurred. I also checked Google Earth. The most recent Google Earth imagery of the landslide scar was from April 21, 2023. It didn’t show the rockslide. Then I checked Sentinel 2 satellite imagery, but that wasn’t high enough resolution to determine the date of the rockslide. High resolution imagery of a relatively small, non-urban area would be required, and it would need to have been taken after April 21, 2023.
After failing to find a suitable image using various services that provide free or low cost imagery, I contacted the Vexcel Data Program. They were kind enough to provide an answer — the new rockslide was not in imagery from September 23, 2023, but was present in an image from October 12, 2023.
The new rockslide occurred about 16 months ago, a month or two after Tropical Storm Hilary passed through Southern California. For the 24-hour period ending at noon on August 21, 2023, the weather station at nearby Circle X Ranch recorded about 3.9 inches of rain.
While searching for imagery of the landslide scar, I stumbled onto UCSB Library’s collection of aerial photography. It contains more than 2.5 million images dating back to the 1920s. Curious to see the quality of the photos, I picked a 1:12,000 scale image from November 1936 that was more or less centered on the landslide scar. The quality of the image is excellent — but where was the landslide? I had assumed the Serrano Canyon Landslide to be an ancient feature. How old is it?
The most recent image I could find without the landslide was from August 1947. The most recent image of the landslide was from October 1959 but it doesn’t show the landslide clearly. The oldest the landslide could be is about 77 years!
The event did not go unnoticed. This 1:16,000 scale aerial photo from February 1961 shows a well-used road going to the landslide. Vehicles are parked at the end of the road and there is activity at the landslide. Here is a before and after comparison of the 1947 and 1961 photos.
Continuing down Serrano Canyon, I stopped at Sycamore Canyon to get some water and decide where I was headed next. Option A was to turn south on Sycamore Canyon Road, go up the Fireline Trail to Overlook Fire Road, and then return to Wendy Drive via Hell Hill, Wood Canyon, Two Foxes, Sycamore Canyon, and Upper Sycamore. Including what I’d already done, that would be about 24 miles. Option B was to turn north on Sycamore Canyon Road and go directly to the Two Foxes Trail, etc. That would be about 20 miles.
Today, I opted for Option B. That turned out to be an exciting choice. Just before the turn onto Wood Canyon, there was a sequence of mountain lion tracks along the east side of Sycamore Canyon Road. To better show its size, I superimposed the track on top of my shoe. The shoe is about 4.5 inches wide at the center of the track. There were also deer tracks along the road.
Here is a high resolution, interactive, 3D terrain view of the Old Boney – Serrano Valley Loop from Wendy Drive. Two options are shown. The map can be zoomed, tilted, rotated, and panned. To change the view, use the control on the upper right side of the screen. Track and placename locations are approximate and subject to errors. Poor weather, and other conditions may make this route unsuitable for this activity.
Some related posts:
– Back on the Old Boney and Serrano Valley Trails
– Old Boney to Serrano Valley, Plus Fireline and Overlook
Clearing clouds along the crest of the Santa Monica Mountains from Bulldog Mtwy fire road. The photograph was taken on a recent run of a variation of the Bulldog Loop.
Some related posts:
– Turning California Sycamore Along Malibu Creek
– Reagan Ranch at Sunrise
The Angeles National Forest Trail Race starts and ends on top of Mt. Wilson. This was the view south over Pasadena and the Los Angeles Basin from the mountain-top parking lot, about an hour and a half before sunrise and the start of the race.
Related post: The Angeles National Forest (Mt. Disappointment) Trail Race Returns
Here are a few images from a meandering run in Malibu Creek State Park on the Cistern, Lookout, Crags Road, Forest, and Chaparral Trails.
Some related posts:
– Spring Fever Running the Phantom Loop in Malibu Creek State Park
– Malibu Creek State Park: Lake Vista Ridge, the Forest Trail, and September Wildflowers
– Afternoon Run on the Forest and Lost Cabin Trails in Malibu Creek State Park
Rocky Peak Road is an exceptionally popular hiking and biking trail that starts at Santa Susana Pass, on the north side of the 118 Freeway. Regardless of the time of day or weather I ALWAYS see someone on this trail.
The plan for this afternoon’s run was to do an out and back on Rocky Peak Road to the top of the Chumash Trail (3.8 miles) or to Fossil Point (4.8 miles).
Another runner was finishing their workout as I started up the initial steep climb. Glistening in the warm sun, runoff from yesterday’s storm streaked some of the sandstone rocks, and ephemeral streams gurgled in the ravines and gullies.
Thanks to the sandstone geology, the dirt road wasn’t as muddy as most other local trails would be. Although heavily eroded from numerous Winter storms, it was still near the top of my list of places to run during periods of wet weather.
In the aftermath of yesterday’s storm the weather was spectacular. The temperature was warm enough to run in shorts and short-sleeves but still comfortable chugging up Rocky Peak Road’s steep hills. Puffy cumulus clouds filled the sky, creating postcard views at every turn.
More focused about getting up the hill than any weather concerns, I continued past the top of the Hummingbird Trail and through a gap in the rocks to a section of road with a good view of the San Fernando Valley and San Gabriel Mountains.
I’d been in a situation similar to this several times on Rocky Peak. As a storm moves east from Los Angeles, energy circulating around the low can sometimes result in “back-door” precipitation. In this scenario, clouds build-up over the mountains to the north and then drift over the San Fernando Valley, producing showers — and sometimes — thunderstorms.
But today’s scenario was a bit more complicated. A much larger area, extending east to the San Gabriel Mountains, was rapidly destabilizing. What had been a picturesque sky at the start of the run was now congested and ominous. The question wasn’t so much if it was going to rain, but if a thunderstorm was going to develop.
As I continued up the road, the sky darkened, the temperature cooled, and the wind became more gusty and fitful. A little chilly, I pulled on my arm sleeves. I laughed nervously as I mistook the roar of a passing jet for thunder. That was a jet, right?
When people say they are “doing Rocky Peak,” they are often referring to a high point on Rocky Peak Road that is west of the actual peak and about 2.4 miles from the trailhead. The final climb to this high point is a good one — gaining about 450 feet over three-quarters of a mile.
The road on this stretch is oriented in such a way that the terrain hides the view to the north. I was anxious to get to the top of the hill so I could get a better idea of what the weather was doing. As I worked up the road, I would occasionally feel the cold splash of a raindrop on one leg or the other.
Nearing the top, I thought, “I may get wet, but at least there’s been no thunder.” Within seconds of that proclamation, and as I reached the highest point, there was a long, loud, crackling peal of thunder.
One look at the sky and all thoughts of continuing to the Chumash Trail were gone. I turned around and started running down the hill, hoping to avoid the worst of the storm.
First one pea-sized hailstone hit the ground, then another, and then a sleety barrage of rain and hail poured from the sky. Instantly soaked, I shuddered as thunder echoed overhead and cold rain ran down my back. Muddy water flowed in rivulets down the sodden road and I cautioned myself to run fast, but not too fast.
I didn’t expect to outrun the storm, but hoped I might move to a part of it that was less intense. And that’s what happened. As I descended, the deluge gradually diminished. Most of the activity seemed to be behind me and a little to the east.
By the time I got down to the Hummingbird Trail, it was only sprinkling. The strong cell that had been over Rocky Peak had drifted southeast, and was now over the Porter Ranch – Northridge area.
National Weather Service Doppler Radar tells the story. At the start of the run there were scattered, mostly weak echoes. At 3:06 pm, as I was starting up the last long hill, a cell northwest of Rocky Peak was developing and drifting southeast. Over the next 16 minutes the cell continued to move southeastward and strengthen, and at 3:22 pm was over the Rocky Peak area. I turned around and started down as the cell moved into that area.
The cell over Rocky Peak continued to strengthen, and at 3:39 pm had drifted over the Porter Ranch – Northridge area. At 3:44 pm the NWS issued a Severe Thunderstorm Warning for Western Los Angeles County.
Here are a GOES-18 satellite loop and Doppler Radar loop that show the development and track of the Rocky Peak thunderstorm.
Some related posts:
– Rainy Weather Running on Rocky Peak Road
– Running Between Raindrops: Chumash Trailhead to Rocky Peak
– Thunderstorm