We stopped for a few moments at the river crossing, where water stood in pools waiting for Winter rain. Instead, cold air flowed down its course, cool and refreshing. From this point there would be little shade. Rarely cold, the climb out from the West Fork San Gabriel River to Shortcut Saddle is often warm, and sometimes debilitating.

From a run at Ahmanson Ranch, now Upper Las Virgenes Canyon Open Space Preserve, Wednesday evening.

The Fossil Trail is a steep, approximately mile-long trail in Pt. Mugu State Park that connects the Upper Sycamore Trail, near its junction with Sycamore Canyon Road, to the Old Boney Trail. The most obvious fossils are shell impressions and remnants found in an exposed layer of sandstone about a tenth of a mile below the Old Boney Trail junction. Some of the shell impressions are palm-sized and larger.

The shells appear to be a type of cockle (Anadara devincta) that is an indicator of Miocene-age formations. (See the Oregon Sea Grant publication "Fossils You Can Find on Oregon Beaches.")  In this case, the fossil exposure appears to be in the Lower Topanga Formation, which is believed to have been formed in the middle to early Miocene, about 20 million years ago.

The shape, thickness and ribbing of this type of shell increases its strength and resistance to crushing -- improving the shell's chances of remaining intact when buried in sediment, and during subsequent geologic processes. This may be one of the reasons it is a prevalent indicator fossil.

The photograph is from Sunday's run from Wendy Drive to Serrano Valley.

Scruffy clouds clung to the mountain ridges and summits, confirmation that a weak cold front was moving through the area, cooling temperatures and stirring up the wind. The forecast for the Santa Monica Mountains National Recreation Area had mentioned 25 to 35 mph winds with gusts to 60 mph. So far the weather in Pt. Mugu State Park had been nearly perfect -- breezy and little chilly, but without the impenetrable winds that can take all the joy out of running.

Only three weeks after the area was burned in the 2008 Sesnon Fire, this yerba santa shrub on the Chumash Trail has started the process of foliage replacement. In many areas along the trail, grasses and other annuals (many invasive) were consumed, but adjacent chaparral shrubs were only scorched. Many of these shrubs look like they will be able to recover through budding of existing stems, rather than crown-sprouting.

Some related posts: Chumash Trail - Sesnon & Simi Fires, Rocky Peak After the Sesnon Fire

A view of the eastern Simi Valley and Simi Hills from Rocky Peak.

From a run in Rocky Peak Park today.

When I woke to the rumble of thunder, rain pounding the roof, and wind roaring in the trees, I wondered if a planned run of the Boney Mountain Half Marathon course with John Dale was going to turn into an epic. Radar and satellite imagery showed subtropical moisture streaming in from the southwest, producing bands of showers and thunderstorms. Things don't always look as bad at the trailhead as they do on weather radar, so I grabbed my gear and headed for Wendy Drive.

Downtown Los Angeles (USC) happened to be under the right cloud yesterday, and recorded 0.02 inch of rain. There's a continuing chance of showers in Southern California through the weekend. The area could use some rain. The last storm to produce more than a couple tenths of inch of rain at Downtown Los Angeles was back on February 24, 2008 -- more than eight months ago.

Last year, California's rain season might have been scripted by Dr. Jekyll and Mr. Hyde. Lowland rain totals and the Sierra snowpack were well above normal through the end of February, and then the spigot was turned off. The storm track shifted north, and California had its driest March to May on record. (The March 29, 2008 post in Ed Berry's Atmospheric Insights blog describes the events that may have led to and maintained this shift.)

Which rain season personality will surface this Winter? Earlier this year the equatorial Pacific tried to transition to El Nino, but the atmosphere didn't cooperate. As measured by the Multivariate ENSO Index (MEI), the ENSO state has returned to the weak La Nina threshold. And as measured by the Global Wind Oscillation (GWO), an uncooperative atmosphere has continued to cycle through a La Nina base state.

This suggests a winter precipitation outlook with a La Nina flavor -- similar to last year. This precipitation map, generated by the ESRL-PSD Composite ENSO plots page, shows the mean November-March precipitation for the U.S. during 9 La Niña events from 1948 to the present. The average La Niña rainfall indicated for coastal Southern California is in the 7.0-10.5 inch range. Last season's November-March rainfall in Downtown Los Angeles was about 12 inches.

Here's the current Nov-Dec-Jan precipitation outlook issued October 16 by the Climate Prediction Center. The "EC" means an equal chance of below normal, near normal, or above normal precipitation. The IRI Multi Model Seasonal Forecast for Nov-Dec-Jan is similar. We'll see what we get!

My run to "Fossil Point" on Rocky Peak road, and side trip to Rocky Peak, was not the appalling experience I've come to expect when investigating a wildland area that has been overrun by a Southern California brush fire. Much of the chaparral along the fire road was not burned. Here are a few photos:

View southeast toward Porter Ranch from the summit of Rocky Peak (larger image).

View north toward Rocky Peak where the trail levels out, about 1.4 miles from the trailhead.

Burned area near viewpoint of Simi Valley about 2.3 miles from the trailhead.

View north from the summit of Rocky Peak. Rocky Peak fire road is on the far left, and the Johnson trail is on the right.

Unburned area along Rocky Peak fire road about 2.8 miles from the trailhead. Rocky Peak is the peak on the left.

False color image of slopes on the southwest side of Blind Canyon. The image has been modified to emphasize burned and unburned areas.

Some related posts: Chumash Trail - Sesnon & Simi Fires, San Fernando Valley from Rocky Peak

This weather worn sandstone boulder is a familiar landmark to those who do the Chumash Trail. It's a little less than a mile up the trail, and is at the point where the trail turns east and continues its climb along a cobble strewn divide. The chaparral here and elsewhere along the Chumash Trail was burned last week by the western flank of the Sesnon fire.

From the Boney Mountain loop a couple of weeks ago.

The scat appeared to be a day or two old, and was much bigger than a coyote's. It was full of fur and could only be from one animal -- a mountain lion. The spot had been used before, and it probably wasn't a coincidence that this was one of the few points along the trail with a good view and nearby cover. I looked into the brush and wondered if unseen eyes looked back.