Cheeseboro Canyon is the prominent canyon on the left of the photo. The dirt road is the Cheeseboro Ridge Trail — a power line service road. The Sheep Corral Trail follows the flat-ish terrain in the little valley. It links the Cheeseboro Ridge Trail to the top of the Cheeseboro Canyon Trail about a quarter-mile to the west (right) at Shepherds’ Flat.
There are innumerable trail runs, hikes and rides that pass through here. Here’s a NPS map of the Cheeseboro/Palo Comado area trails (PDF). On this cool, mid-January day I was doing the Upper Las Virgenes Canyon – Cheeseboro Ridge Loop.
Originally posted January 7, 2016 and rewritten to reflect the current rainfall totals for Downtown Los Angeles.
Based on 1981-2010 climate normals Downtown Los Angeles (USC) receives, on average, 1.04 inches of rain in November, 2.33 inches of rain in December, and 3. 12 inches in January. This past November Los Angeles recorded only 0.01 inch of rain, and in December only 0.57 inch. January rainfall was a few hundredths above normal at 3.17 inches.
The 2015-16 El Nino is one of the three strongest El Ninos in the past 65 years; the other two were 1982-83 and 1997-98. How does the amount of rain we’ve had so far this rainfall year compare to the other two? Is this El Nino failing to produce the expected amount of rainfall in Los Angeles?
On January 7, when this post was originally written, the rain year totals were in the same ballpark for the date as during the 1982-83 and 1997-98 El Ninos. That is no longer the case, and Los Angeles rainfall totals are falling far behind those other big El Ninos.
As of January 31 Downtown Los Angeles (USC) has recorded only 6.97 inches of rain for this rain year, which is 0.47 inch below normal. At this point during the 1982-83 El Nino Los Angeles had already recorded 12.98 inches of rain, and in the 1997-98 El Nino 9.15 inches.
The good news is that the Sierra snowpack is above average. That helps with the water supply, but not so much with naturally-occurring local groundwater and other drought impacts in Southern California. It does help that the Los Angeles rain year total is nearly normal, but I’m still waiting to see running water in upper Las Virgenes Creek.
Remarkably, as of this morning, the medium range models are forecasting dry weather to predominate over the next 10 days or so and both the GFS and ECMWF show a mega-ridge of high pressure developing over the West Coast this weekend. We’ll see!
For the most part the upper layer of clouds had been above Boney Mountain. Thin wisps of cloud had clung to the ridges in a couple of places, but the ceiling looked like it was going to remain above the peak.
Fog changes the mood and character of a place, particularly a place where airy views and an expansive mindset are the norm. Thoughts turn inward and perceptions more narrowly focused. The big picture becomes entirely virtual.
Earlier in the week the area had been drenched by more than two inches of rain. It had been damp overnight and water filled the profusion of irregular pockets covering the volcanic rock. The rock was plastered with a patchwork of bright green moss and gray-green lichen. Saturated with water, the moss was slippery as ice. I climbed with extra care, especially on the steeper sections.
Where soil collected on tiered steps, obovate leaves of shooting-star and other annuals sprouted, presaging a show of the purple and yellow wildflowers. Chalk liveforever relished the moisture, its drought-scarred leaves rehydrating and recovering.
Higher on the ridge the intricate green foliage of red shanks, still recovering from the 2013 Springs Fire, was heavily-beaded with water. Brushing against it was like being sprayed with ice-cold water.
The last couple of days I’d been checking the weather models to try and get an idea of when the cold front might reach Pt. Mugu State Park. Projections ranged from around 10:00 AM to about 1:00 PM.
A group of us were doing an annual end of the year trail run and scramble over Boney Mountain to the Backbone Trail, and then returning by various routes to the Wendy Drive trailhead. Along the way there are great views of the Boney Mountain Wilderness, Channel Islands, Conejo Valley and Ventura Mountains, but you can’t see very far from inside of a cloud.
It turned out clouds would not be a problem. At least not the first half of the day. When I pulled into the parking area at Wendy Drive the front was little more than a white smudge on the western horizon. The sky was clear and it remained clear the entire time we worked up Boney’s Western Ridge. Everyone enjoyed scrambling up the gullies and rocks to the top of the mountain and then over to Tri Peaks.
We’d reached Tri Peaks about 40 minutes ago. From there I’d run over to Sandstone Peak, the highest peak in the Santa Monica Mountains. From this panoramic vantage point I could see the front was still well to the west, near Santa Barbara. This gave me some time. I was prepared for rain, but didn’t want to miss the wonderful scenery running down the Chamberlain Trail, over to Serrano Valley, and through Serrano Canyon.
Over the remainder of the run I watched as cirrus clouds ahead of the front gradually muted the sun, mid-level clouds began to develop over the peaks, and the wind became more gusty and fitful. Later in the run the clouds started to lower and thicken and the temperature dropped. Eventually it began to smell like rain.
As I crested the hill on Danielson Road I felt a cold drop of rain on my arm and then another on the back of a leg. Clouds covered the sky, and to the west showers draped the ridges and filled the canyons. The front and I were racing the last mile to the trailhead, and I knew who had won.
Due in part to El Nino and the Madden-Julian Oscillation (MJO) Southern California jump-started the 2015-16 rain season with above average rainfall in July and September.
Last year the NWS changed the WATER Year to October 1 – September 30, but the RAINFALL Year remains July 1 – June 30, as it’s been for decades.
Below is the monthly tabulation of rainfall for Downtown Los Angeles (USC) for the 2015-16 Rainfall Year, along with what is considered normal for the month.
Downtown Los Angeles Rainfall
So far this rainfall year Downtown Los Angeles (USC) has recorded 3.23 inches. Even with November as dry as it’s been we’re still more than an inch above normal for the rainfall year — about 1.46 inches above normal as of November 25.
Over the next couple of weeks the medium range models and other tools aren’t especially bullish on our chances for a good, soaking rainstorm in Southern California. Longer term guidance suggests an improving chance of precipitation as December progresses, and above average precipitation in January and February. We’ll see!
The title photo is from November 3. It shows a band of thunderstorms that moved southward across the San Fernando Valley and into the Santa Monica Mountains. The band produced cloud to ground lightning strikes and some heavy showers. Saddle Peak is in the distance on the left. The shower activity in the distance on the right is in the area of Kanan Rd. and the 101 Frwy.