After skiing Mt. San Jacinto (10,834') last week, Charles and I decided to take advantage of the good snow and ski the peak again today. Warming temperatures had thinned the snowpack a bit, particularly on the flats in Long Valley (8400'), but there was still plenty of snow.

The temperature was a little cooler than last week, particularly on the summit, where a brisk west wind increased the wind chill. I didn't dig my better gloves out of the pack, and the light (knit) gloves I used for skiing up were like wearing no gloves at all. After spending fifteen cold minutes on the summit, I bailed to the south side of the peak, near the summit hut, and warmed up.

Once again, there was outstanding skiing on the sun-warmed slopes to the south and southeast of the summit. The surface of the snow had been transformed into a velvet-like layer of fine-grained corn snow. You couldn't pick a bad line, and Charles and I would yell at each other, "you've got to see the snow over here!"

Conditions were more variable in the trees on the east-facing slopes above Tamarack Valley, but there were still some excellent sections out in the sun. Threading our way through the trees on the low angle slopes leading to the Round Valley Trail was fun, and in an peculiar way, so was skiing the well-traveled snowshoe track down the trail to Long Valley.

The title photo is of Long Valley Creek below Round Valley. As the snowpack melts, deep wells and moats typically form along streams. These can be anything from an inconvenience, to a life-threatening hazard that is impossible to cross. Snow bridges melt from below, as well as above, and are difficult to evaluate. It can be unnerving to cross a large Sierra creek on a snow bridge in the Spring, when no other option is available.

Here are a few additional photos. Click for a larger image and description:

Round Valley Trail Bowl Below Miller Peak Summit of Mt. San Jacinto

If you were going to pick the most pleasant conditions possible to ski San Jacinto Peak (10,834'), today's weather would be hard to top. The midday temperature on the summit of the peak was around 40-45 degrees. Winds were light, and it was pull-up-your-sleeves warm -- but not broiling -- most of the way up the peak.

There was still a lot of untracked snow from last week's storm, and overall the snow conditions were very good, especially on the steeper, sun warmed slopes southeast of the summit, and in the trees lower on the peak. Here are a few additional photos. Click for a larger image and description:

Cornell Peak Above Tamarack Valley East Ridge of Mt. San Jacinto Below Summit of Mt. San Jacinto

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.

50K Runners Returning from the Rocky Peak Trailhead

Cool temps, clearing skies, and snowy vistas greeted runners doing the 2011 edition of the Bandit trail races at Corriganville Park in Simi Valley, California.

If you're going to have a trail race after a rainstorm, Rocky Peak is the place to do it. Rain gauges in the area recorded as much as two inches of rain in the 48 hours leading up to the race, and for a while it looked like there might be a dusting of snow on the highest points of the course. Except for a couple of short muddy sections, and having to dodge a few mud puddles, the dirt roads and trails were in good shape.

This year the race was expanded to include a 50K. This new option doubled the fun on the Chumash-Las Llajas loop of the 30K course, running the loop twice, and also took a short sightseeing trip down to the Rocky Peak trailhead at Santa Susana Pass. The 30K course was the same as last year, but the 15K course was shortened from last year's 16K or so to 15K.

The 50K course is a tough one, including about 7 miles of technical single track trail, 22 miles of fire road, and a mile of paved road. The elevation gain/loss is about 5400', which is a little more than the Bulldog 50K course, and a little less than the original Mt. Disappointment 50K course. Here's an elevation profile of the Bandit 50K course.

There are several difficult stretches on the 50K course. Just a mile into the race runners have to deal with a very steep climb -- an 800 foot ascent in just one mile. In my mind it's the most important mile on the course, and how hard you push here can have a big effect on how you feel over the next 28 miles! There are a couple of other long climbs. The 2.3 mile climb from the Rocky Peak trailhead to the top of the Rocky Peak grade gains over 1000', and the gain over the 1.75 miles from the Las Llajas split to the highpoint at Shells/Fossil Point is 800'. Runners doing the 50K get to do the Las Llajas to Shells climb twice.

One of the toughest sections for me was the run up Las Llajas Canyon on the second Chumash-Las Llajas loop. This section starts at about mile 19 and ends at the Las Llajas split, where the road forks right and up through the oil fields. For the most part the grade is not steep, but the miles are deceptively long and grueling. Also tough on tired legs is the very technical plunge back down to Corriganville at the end of the race.

Congrats to 50K winners Chris Price and Nancy Ishizawa. Clearly enjoying the day, Chris flew through course in a remarkable time of 4:12:51, averaging 8:28 minute miles. In the 30K Marcelo Mejia set a new course record with a blazing time of 2:52:31. On a slightly shorter course than last year, Fernando Ramirez and Jen Todd put down fast 15K times. For all the results and race photos, see the Bandit web site.

All in all it was fantastic day for a run! Many thanks to the race organizers -- Randy & Sarita Shoemaker, Larry Lee, and Todd Baker -- and all the volunteers and sponsors for an outstanding event!

Here are a few additional photos. Click for a larger image and description:

Start of 800' Corriganville Climb	Running Up from Rocky Peak Trailhead	Snow on Ventura Mountains
15K Runner Headed Back	Descending Chumash	Casey's Water Cache

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.

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.

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

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.

It's now been 17 days since there's been measurable rain at Downtown Los Angeles (USC). A trace of rain was recorded on a couple of days, but for the time being a big blocking ridge has shut the door on Pacific precipitation.

So far this January, only 0.58 of rain has been recorded, which is a little less than one-third of normal for the month. However, because of our frequent December storms the water year total at Los Angeles is currently about double the normal amount -- and why open space areas of Southern California have turned so lush and green.

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?

These rare clouds -- a mid-level form of mammatus -- were over the western San Fernando Valley last Thursday afternoon, January 6, 2011. They were produced by the moisture and dynamics associated with a closed upper level low that was about 390 miles WSW of Los Angeles, and moving ENE at about 17 mph.

I first noticed the mammatus clouds around 3:30 p.m. About 30 minutes later, when I started my trail run in the Simi Hills, the cloud band had shifted a couple of miles to the WNW, but the mammatus was still present. The title photograph was taken just a few minutes into the run, at about 4:07. This uncropped version of the image shows the clouds in relation to the terrain.

The mammatus was in the leading band of a series of cloud bands slowly moving from the ESE to the WNW. Over the next 30 minutes the mammatus mostly dissipated, as the cloud band became disrupted by shear. During this period the bands evolved into a wave-like sequence of bulbous clouds that had some of the characteristics of mammatus, but were not multi-lobed. The bases of these clouds were ragged -- an indication that snow showers were sublimating in the dry air below. The photograph of the cloud sequence was taken at about 4:37 p.m. Some remnants of mammatus could still be seen in the sheared leading band.

The circumstances in which mammatus is observed and some possible mechanisms for its formation are discussed in the 2006 paper, The Mysteries of Mammatus Clouds: Observations and Formation Mechanisms by David M. Schultz, et al.

Based on a NAM analysis for Van Nuys and NKX (San Diego, CA) sounding, the atmospheric profile was consistent with real-time soundings when mammatus is present. A BUFKIT model sounding based on NAM data for 4:00 p.m., shows a moist layer from about 14,000 ft. to 23,000 ft., with a dry subcloud layer. The freezing level was indicated at about 8500 ft. A plot of vorticity from NAM data indicated a vorticity lobe in the area at the time the clouds were observed. As can be seen in both photographs, there was also strong shear between 20,000 ft. and 25,000 ft. A superadiabatic subcloud layer is not present in the soundings, but cooling from subcloud evaporation or sublimation might create one.

The photograph in the post Simi Hills to the San Gabriel Mountains was also taken on this trail run.

A view from the Simi Hills, across the San Fernando Valley, to the San Gabriel Mountains.

From today's trail run in the Simi Hills.