Category Archives: nature|weather

Looking for Snow in the Santa Monica Mountains

View from Sandstone Peak, the highest point in the Santa Monica Mountains

Perhaps the only thing more difficult than forecasting rain in Los Angeles is forecasting snow in Los Angeles. A NWS Winter Weather Advisory issued Friday evening for the Santa Monica Mountains Recreation Area forecast the snow level to drop overnight from above 3000′ to between 1000′ and 1500′. Snow accumulations from 1 to 3 inches were expected.

When getting ready for a run on those searing 100 degree days at Ahmanson Ranch, I look longingly at the Lasky Mesa snow photos from 1943 displayed in the information kiosk at the Victory Trailhead. Would that rare snow scene be repeated? If so, I wanted to see it. I’m a skier from way back, but snow in the hills near my Los Angeles area home is an altogether different thing.

Last weekend it looked like we might get some snow on the higher parts of Rocky Peak Road for the Bandit 15K/30K/50K trail runs. There was some snow on Oat Mountain, but not down to Rocky Peak. The Rocky Peak area is about 500′-1000′ higher than Lasky Mesa, so snow there isn’t quite as rare. The last time I ran in the snow on Rocky Peak Road was in December 2008, and before that in March 2006.



Snow is an iffy thing in the Los Angeles area. The ocean is the dominant moderating influence. Storms generally bring in air warmed by the ocean, and the coldest air often doesn’t move in until after most of the precipitation has ended. To get low elevation snow, the timing and conditions have to be just so. Whether it snowed or not, it looked like it would be an interesting weather day, so I planned to get up early and do a morning run.

At dawn the lack of snow on the local foothills made it plainly evident that all the ingredients required for very low elevation snow had not come together.  Overnight there had plenty of snow — four feet of it at 7500′ at Mt. Baldy — just not much low elevation snow. (Later in the day post frontal convection would produce some isolated showers of icy snow in the east San Fernando Valley and La Crescenta.)

On the off chance there had been a dusting of snow at the higher elevations of the Santa Monica Mountains, I decided to do the Mishe Mokwa – Backbone Trail loop and check out the conditions on 3111′ Sandstone Peak, the highest peak in the range.



What a great morning for a trail run! When I started the loop, it was partly cloudy and the temperature at the Mishe Mokwa trailhead (el. about 2100′) was a chilly 37 degrees. The ground was soaked, and the chaparral wet with rain. Streams filled every gulch and gully, and the gorge along Echo Cliffs roared with runoff. Level sections of the Mishe Mokwa Trail were nearly one continuous puddle. Two creek crossings — one at Split Rock and another near the Backbone Trail — were wide enough to require wading.

Running the rocky trail with care, it took a little under an hour to reach the Backbone Trail junction. As I puffed up the trail toward Sandstone Peak, each exhalation was visible. I found myself reveling in each frosty cloud, as it would hang briefly in the morning sun, and then dissipate.

Although I could see no snow, it was cold enough that I thought there was a chance there might be some residual snow in the shade on the northwest side of the peak. Rounding the corner, I started up the makeshift stairs at the beginning of the spur tail leading to the summit. On top it was cold, windy, wet and spectacular, but — sigh — there was no snow.

Note: The rain from this storm pushed the water year rainfall total for Downtown Los Angeles to above the 100% mark. Although this might seem unusual in a La Nina influenced rain season, during two of the strongest La Ninas in the past 60 years — 1955-56 and 1973-74 — Los Angeles recorded 99% and 106% of normal rainfall.

Jet Stream Cirrus

Jet stream cirrus

The long streaks in the photograph above are cirrus clouds embedded in a 125 kt jet stream that was positioned over Southern California Thursday afternoon.



The jet stream was at an altitude of about 30,000 ft. and associated with an upper level low pressure trough off the coast. This trough is the source of the disturbances that are resulting in our latest bout of wet weather.

The jet stream is a key feature of the earth’s atmospheric circulation, and plays an important role in both weather and climate.

For more about jet stream cirrus see A Composite and Microphysical Study of Jet Stream Cirrus Over the ARM Site.

The photographs are from a trail run on Thursday.

Satwiwa Shadows & Sun

Satwiwa from Danielson Rd.

By the time I reached Rancho Sierra Vista/Satwiwa at the end of last Sunday’s wet run to Serrano Valley and back, the frontal band was mostly done with its showers and was speeding to the east. In its wake were blustery winds, broken clouds, and a dynamic patchwork of sun and shadow on Satwiwa’s spectacularly green landscape.

Showery Sunday

Boney Mountain from the Old Boney Trail

Boney Mountain from the Old Boney Trail

It started to sprinkle as I walked from my car to the Wendy Drive trailhead. In a matter of minutes the sprinkles turned to a light, but steady rain, and the Satwiwa trail started to become slick with mud. The rainy weather would continue through most of my run in Pt. Mugu State Park.



It was wet today, but today’s rain was the first in Southern California in nearly a month. Southern California was very wet from October through December, but the storm door from the Pacific into California slammed shut in early January. The weeks of wet weather followed by weeks of warm, dry weather has the plant communities of the Santa Monica Mountains thinking it’s Spring.

Among the flowers blooming along the Old Boney and Serrano Valley trails were paintbrush, encelia, milkmaids, phlox, shooting star, nightshade, wild cucumber, canyon sunflower, deerweed, and bigpod ceanothus. But more than the plants have responded. On January 17, trail runner Howard Cohen took this video of a sizable rattlesnake on the Old Boney Trail!

Some related posts: Serrano Valley from Wendy Drive, Serrano Valley from the Chamberlain Trail

Oak, Hill & Wave Clouds

Mountain wave clouds

These mountain wave clouds were produced by north-northeast winds blowing across the generally east-west oriented mountain ranges north and northwest of Los Angeles. The clouds form near the crests of the undulating airflow downwind of the mountains.

The cirrus veils trailing downwind from the clouds are comprised of ice crystals. There was little shear, so the wisps and sheets of cirrus are aligned with the wind and perpendicular to the long axis of the cloud. Compare to the cirrus veil of these lenticular clouds, also formed by north-northeast winds, but which were being sheared by northwesterly winds.

From a trail run at Ahmanson Ranch on Thursday.

Bandit Training

Top of the Wildlife Corridor Trail

What a difference 5 days makes! In the cold morning shadows before the start of the Boney Mountain race last Sunday, the dew on the fences was frozen and frost was everywhere. This morning in Corriganville Park the temperature was a balmy 65 or so, and the high was expected to be around eighty.

Today I was running the Bandit 30K course as part of a training run organized by Bandit 15K/30K/50K R.D. Randy Shoemaker. Good thing too. Even though these are my backyard trails, it reminded me just how tough these courses are. The numbers — about 3300 ft. of gain/loss over 19.5 miles for the 30K — don’t tell the whole story.



The title photograph is of runners at the top of the Wildlife Corridor Trail. This gnarly trail links Corriganville Park to Rocky Peak Road, and it is just one of the special treats you’ll encounter on the 15K, 30K and 50K courses. I don’t know if it tougher going up, when your legs are fresh; or going down, when your legs are worked. From personal experience I know it is really easy to push too hard on this climb, and mutter to yourself, “Why did I do that?” for the remainder of the race.

Today, the conditions could not have been better. Well, if we’re going to nitpick, maybe a little less wind. But who can complain on a January day when skies are blue, the hills are green, and the temperature is in the seventies?