Category Archives: clouds

Running Between Raindrops: Chumash Trailhead to Rocky Peak

Rain in the San Fernando Valley from Rocky Peak. March 12, 2021.
Rain in the San Fernando Valley from Rocky Peak

Was that thunder? I warily eyed the dark clouds over the mountains and pondered the situation.

I was about halfway to the top of the Chumash Trail and was planning to run along the crest to Rocky Peak. The run had started in short sleeves and sunshine, but it was pretty obvious that wasn’t going to last.

Chumash Trail about a mile from the trailhead
Chumash Trail about a mile from the trailhead

A cold upper-level low had brought badly needed rain to the area for the past two days. The low was moving off to the east, but there was still a chance of afternoon showers and maybe even a thunderstorm.

It was the “thunderstorm” part that I needed to pay attention to. I had enough gear to deal with a downpour and cooling temps, but electrical storms are no fun at all.

I decided to continue to the top of the Chumash Trail and reassess. As I worked up the trail, I pictured the counterclockwise circulation around the low, and how convective cells develop over the mountains and then dissipate as they drift south. The concern was that the cells don’t always dissipate.

Rocky Peak Road near Rocky Peak
Rocky Peak Road near Rocky Peak

It looked like things weren’t getting any better at the top of the Chumash Trail, but it wasn’t worse either. I hadn’t heard any thunder for a while, and most of the activity seemed to be a few miles to the west and east. Having been starved of stormy weather for much of the rain season, I turned right on Rocky Peak Road and headed south toward Rocky Peak.

The run from the Chumash Trailhead to Rocky Peak is a challenging mix of technical single-track trail and hilly fire road. There are wide-ranging views of Simi Valley & Simi Hills, the San Fernando Valley, Santa Monica Mountains, Ventura County mountains, and San Gabriel Mountains. On a clear day, the view can extend to the Channel Islands, Saddleback, and San Jacinto Peak.

NOAA radar mosaic Rocky Peak March 12, 2021.
NOAA radar mosaic at the time I was on Rocky Peak

The actual turnaround point for a run to “Rocky Peak” varies. Some like to turnaround at the high point of Rocky Peak Road that is near Rocky Peak. Most of the time, I turnaround at a viewpoint that is at the end of a spur trail that branches off from the high point of Rocky Peak Road. From time to time, it’s fun to hike over to Rocky Peak and scramble to the top. That’s a bit more involved and requires some route-finding.

I felt the first raindrops as I reached the high point on Rocky Peak Road and turned onto the spur trail that leads to the overlook. There was some increased development to the east, but it looked like there would be enough time to get over to Rocky Peak, take a couple of pics, and then head back.

Oat Mountain, shrouded by rain
Oat Mountain, shrouded by rain

I felt a little exposed on top of Rocky Peak. I hadn’t heard any thunder for the past hour, but a cell to the east was spouting heavy rain over the San Fernando Valley, which meant there was probably enough development to produce lightning. I took the title photo and a couple of others and hurriedly descended from the peak.

Back on Rock Peak Road, the sprinkles increased, and the showers became more steady as I ran north toward the Chumash Trail. Under the dark clouds, a raven perched on a large pinnacle cawed incessantly, either enjoying the rain or complaining about it. In the distance, a siren wailed down in the valley. It was cold, and I was very glad to have an extra shirt, sleeves, gloves and a light rain shell.

Mix of sun and rain on the Chumash Trail
Mix of sun and rain on the Chumash Trail.

As I began the descent of the Chumash Trail, the sun briefly broke through the clouds, reflecting brightly on the wet sandstone rocks. I breathed deeply, relishing the smell of the cleansed air and wet chaparral, and continued down the trail.

Here’s an interactive 3D terrain view of my GPS track. Over the run, the temperature sensor on my pack recorded a drop of about 30 degrees — from around 70°F at the start of the run to about 40°F when the showers began! Here’s what a NOAA Radar Mosaic looked like at the start of the run and when I was on Rocky Peak.

Related: Chumash Trail, Rocky Peak, Thunderstorm

Blue Skies, Sunshine and Windstorm After Windstorm

blue sky, sunshine, high clouds and a trail on a hill

It looks like Downtown Los Angeles (USC) is going to end February — one of the wettest months of the rain year — with only a trace of rain. The current rain year total for Los Angeles is 4.39 inches, which is about 39% of the normal total for this date.

It’s been one of those years where missed rain opportunities have often turned into strong offshore wind events. This chart from MesoWest shows the wind speed and direction for the past 30 days for the Malibu Hills RAWS. Since mid February there has been five wind events with sustained wind speeds over 30 mph and gusts over 50 mph.

Current forecasts suggest Los Angeles will see at least some rain in March, with the first chance around midweek. We’ll see!

Related post: A Dry and Dusty Start to the Los Angeles Rain Year

Chasing a Sunrise, Taking a Moonshot, Los Padres Snow, and a Dark Line in the Sky

Colorful sunrise in the eastern Santa Monica Mountains

I was running up Calabasas Peak Mtwy fire road trying to get a better view of the eastern sky, but the view in that direction was blocked by a steep hillside. The road turned to the northeast up ahead, and I hoped the best moments of a rapidly-evolving sunrise would not be lost.

A couple of breathless minutes later, I rounded a corner and was rewarded with an unobstructed view of a vivid, pink-red-orange mackerel sky. Focusing on the ridgeline near Topanga tower, I shot several sets of bracketed photos.

Handheld snapshot of the Moon, using a Lumix ZS100
Handheld snapshot of the Moon. Click for larger image and more info.

Excited by the sunrise, I continued up the fire road, scanning my surroundings for another photo. My eye settled on the gibbous moon. High in the sky, it’s bright face was subdued by a thin veil of pinkish-gray cloud. I’d previously experimented with handheld shots of the Moon using my running camera — a Lumix ZS100. Zooming to an equivalent focal length of about 250mm, I held my breath, steadied the camera the best I could, and took a few shots. Here’s one of the images — cropped and sharpened — with enough detail to see craters, maria, and some other lunar features.

At the bottom of Topanga Lookout Ridge there were several bigberry manzanita bushes covered with flowers. A hummingbird was up before sunrise, buzzing about the blossoms, busily drinking the precious nectar. Although it had rained a couple days before, this rain year there had been little rainfall, and a corresponding scarcity of early season wildflowers.

As I climbed higher on the ridge, the mountains northwest of Los Angeles came into view, white with snow from the recent storm. The snow-covered peaks are south of Mt. Pinos and Frazier Mountain, in the area of San Raphael Peak, McDonald Peak, Sewart Mountain and Snowy Peak.

Contrail shadow near Los Angeles
Contrail shadow.

Like snow on a mountain, there is a purity in the form and appearance of clouds. When a long, dark streak appeared across a layer of high clouds, it was hard to miss. In this case, the dark line appears to be the shadow of a contrail of a jet flying above the clouds. At the time LAX was reporting scattered clouds at 19,000′ and 23,000′, with a broken layer of clouds at 28,000′. Given the height of the clouds and orientation of the contrail, it may have been from a flight from San Diego to San Francisco.

Topping out on the ridge, I smiled when I saw the masked couple dancing on the Lookout, and continued west toward Saddle Peak.

Some related photos: An Early Morning Dance at Topanga Lookout, Fallstreak Hole, Rainbow Colors in Cirrus Clouds Over Los Angeles

Winter Sky: Cirrocumulus Clouds

Cirrocumulus clouds from Upper Las Virgenes Canyon Open Space Preserve, also known as Ahmanson Ranch

Cirrocumulus clouds form at high altitude. They are primarily composed of ice crystals but also contain supercooled water droplets.

The photograph of cirrocumulus clouds was taken in Las Virgenes Canyon on a trail run from the Victory Trailhead of Upper Las Virgenes Canyon Open Space Preserve, also known as Ahmanson Ranch.

Some related posts: Pattern Change Ahead, Fallstreak Hole, Rainbow Colors in Cirrus Clouds Over Los Angeles

Explosive Growth of the Lake Fire

Development of Lake Fire pyrocumulus cloud over 10 minutes
Growth of the Lake Fire in just 10 minutes.

Lake Fire pyrocumulus cloud at about 4:21 p.m.
Lake Fire pyrocumulus cloud at about 4:51 p.m.

The photographs above show the rapid development of the pyrocumulus clouds associated with the Lake Fire, near Lake Hughes. The timestamps are approximate.

According to the Lake Fire incident page, the fire was first reported on August 12th at 3:40 p.m.

The photographs were taken during a run at Sage Ranch Park. This is the location of the Sage Peak1 and Sage Peak2 ALERTWildfire cams.

Related post: Did Lightning Start the 2002 Curve Fire?