Category Archives: weather|southern california

Caught in a Thunderstorm on Rocky Peak

Sun and gathering clouds on Rocky Peak Road before a strong thunderstorm
Sun and gathering clouds on Rocky Peak Road

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 some other local trails. Although heavily eroded from numerous Winter storms, it is 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.

Clouds developing over the San Fernando Valley (thumbnail)
Clouds developing over the San Fernando Valley

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.

Doppler radar of strong thunderstorm over Rocky Peak (Thumbnail)
Doppler radar of strong thunderstorm over Rocky Peak

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.

Severe thunderstorm over Porter Ranch - Northridge area (Thumbnail)
Severe thunderstorm moving into the Porter Ranch – Northridge area

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

Trippet Ranch Loop, Musch and Garapito Trails – February 2024

Mountain bikers at the Hub in Topanga State Park
Mountain bikers at the Hub

It’s uncommon to have back-to-back Rain Years with 20+ inches of rain in Los Angeles. During Rain Year 2022-2023, Downtown Los Angeles (USC) recorded 28.4 inches of rain — about two times normal. This rain year Los Angeles has already had about 21 inches of rain, so another big year is in progress.

Curious to see how the trail conditions compare to last year, on February 17th and 25th I ran the Trippet Ranch Loop in Topanga State Park.

The big surprise was that the fire roads on the loop — Fire Road #30, Eagle Springs Fire Road, and a short section of Eagle Rock Fire Road — generally fared better than last year. Fire Road #30 had some damage along it’s shoulder, but I did not see the numerous mudslides along these roads like last year.

Wet and muddy section of the Musch Trail. February 2024. (Thumbnail)
A little mud on the Musch Trail.

The news on the trails was divided. One of the more unusual events occurred where the Garapito Trail crosses the east fork of Garapito Creek. A mudslide from a gully on the northwest side of the creek crossed the creek, and left a pile of debris on the trail. The stream may have been dammed by mud and debris for a short time. Farther up the trail, about a half-mile from Eagle Rock Fire Road, a section of the trail collapsed in a slide.

The Musch Trail was very muddy and wet in the usual places. There were a couple of slides along the trail, but all things considered, the trail was in OK shape. The Bent Arrow Trail remains closed as a result of previous storm damage.

Last year, the bloom of bigpod Ceanothus was well underway in early January. This year the bloom began about a month later but is now happening in a big way. Greenbark Ceanothus is also starting to bloom. Some peonies were blooming on an east-facing slope of the Garapito Trail, and a Fuchsia-flowered gooseberry was in bloom near Fire Road #30.

Here are some photos taken on these two runs.

Some related posts:
Popular Trails in Topanga State Park Damaged by Winter Storms
Wettest 14 Months in Los Angeles in 134 Years
Rainy Season Trail Running on the Backbone Trail

East Las Virgenes Canyon After a Seventh Day of Rain

East Las Virgenes Canyon After a Seventh Day of Rain

A very wet East Las Virgenes Canyon and Trail on February 8, 2024,  following seven days of rain. This was by far the wettest start to February in Los Angeles since recordkeeping began in July 1877.

Related post: Ahmanson Ranch and Upper Las Virgenes Creek After Six Days of Rain

Spring Wildflowers in December?

Paintbrush blooming in mid-December in Cheeseboro Canyon in Southern California near Los Angeles
Paintbrush blooming in mid-December in Cheeseboro Canyon

The paintbrush above, and the following Spring-blooming wildflowers were photographed on December 14,2023, on a trail run from the Victory Trailhead of Upper Las Virgenes Canyon Open Space Preserve. With the exception of the black mustard, the wildflowers were found along a half-mile stretch of dirt road connecting upper Las Virgenes and Cheeseboro Canyons.

The false Spring was the result of rain from Tropical Storm Hilary in August, an extended period of wetter than normal weather, and somewhat warmer Fall temperatures. The Water Year that ended September 30, 2023 was the seventh wettest on record for Los Angeles and Calendar Year 2023 was the sixth wettest.

Some related posts:
– A Second Spring at Ahmanson Ranch
– Seventh Wettest Water Year in Los Angeles Results in Rarely Seen Trail Conditions
– Looking For Local Impacts of Tropical Storm Hilary

 

Chumash Rock and Clouds

Chumash Rock and Clouds - Photography by Gary Valle'
Chumash Rock and Clouds

“Chumash Rock” is prominent rock formation seen from the Chumash Trail in the eastern Simi Valley.

As I discovered in a January 2006 adventure, it is not an easy rock formation to reach.

The title photo was taken in mid-November while doing the Chumash – Las Llajas Loop. The clouds over the Ventura County foothills and mountains from the Las Llajas Canyon – Rocky Peak Road connector were just as beautiful.