Developing thunderstorm over the Acton area, north of Los Angeles, from Ahmanson Ranch near the Los Angeles County – Ventura County border. The photo was taken about 4:10 p.m. PDT today, during another hot and humid Ahmanson run.
Cloud tops were reported to be over 50,000 feet. The distance from Ahmanson Ranch (now Upper Las Virgenes Canyon Open Space Preserve) to Acton is about 35 miles.
I rounded the corner, driving from deep shade into the golden glare of the rising sun. There was almost no traffic on Angeles Crest Highway. Up ahead, in the shade of some trees, there was something in the road. Was it a rock or a pine cone? Driving into the sun it was hard to tell. At this time of the morning — before the CalTrans truck has swept the road — one small rock can ruin your whole day. Getting to the trailhead unscathed is always the first challenge of the day.
Today, Craig and I were planning to do a point to point run from Inspiration Point to Islip Saddle — one of the best stretches of trail in the San Gabriel Mountains.
PCTA volunteer Ray Drasher often takes care of clearing the trees from this section of the Pacific Crest Trail. It’s quite an undertaking to get the required stock and equipment to the trailhead and then cut trees spread over several miles of trail. Because of conflicting reports, Ray wasn’t sure whether there were trees still on the trail or not. We’d let him know after the run.
On the drive up you could see it was going to be a spectacular day in the Angeles high country. A low pressure trough moving through central California had pulled in the marine layer and a tumultuous ocean of cloud reached from the south-facing canyons far out over the Pacific.
I drove through the double tunnels at Mt. Williamson and then around a left-hand curve. Up ahead I could see the northwest ridge of Mt. Islip dropping down to Islip Saddle. What the heck? Orange cones? The gate is closed? The HIGHWAY is closed? That didn’t make sense; the Winter closure had ended weeks before.
After parking, I talked to a hiker who said it was closed for “road work.” I assumed there must have been a rock slide in one of the problematic areas between Islip Saddle and Vincent Gap. Later I learned the problem was a “sink hole” west of the Grassy Hollow Visitor Center.
After Craig arrived we discussed route options to Mt. Baden-Powell. Either we did the South Fork loop, which I’d done a couple weeks before, or we did an out and back on the PCT. We opted for the out and back.
The run was as spectacular as expected. The visibility above the deck of stratus was at least 100 miles. San Bernardino Peak, San Gorgonio Mountain and San Jacinto were easy marks to the east and Owens Peak and the Southern Sierra could be seen to the north. Before it was immersed in a tide of cloud, the summit of Santiago Peak (Saddleback) had been visible to the south. High clouds and a gusty westerly wind kept the temperatures moderate. Only one very small patch of snow remained on the trail.
I’d hoped to be able to tell Ray the trees had been cleared from the trail, but no — they were still there. He said the next time I ran there, they would be gone. Thanks Ray!
This is a view of East Las Virgenes Canyon from the power line service road that connects the Las Virgenes Canyon Trailhead to Cheeseboro Ridge. East Las Virgenes Canyon is part of the Upper Las Virgenes Canyon Open Space Preserve (formerly Ahmanson Ranch).
From this afternoon’s keyhole loop run from the Victory Trailhead to Cheeseboro Ridge.
Ahead of another rainstorm, offshore pressure gradients had weakened and the onshore flow was rapidly increasing, pushing marine layer clouds into the coastal canyons of the Santa Monica Mountains and spilling over the low points of the crest.
My first stop was going to be Temescal Peak. This little peak is about 3.5 miles from the trailhead, near the junction of Temescal Ridge fire road and the Backbone Trail. It’s a nice way to start a run, and on a clear day it can have surprisingly extensive views.
The answer to that question turned out to be no. In fact I could barely see my nose from Temescal Peak. In the 12 minutes it had taken me to get to the peak from the Hub the entire area, including the summit of Temescal Peak (about 2100′), had become enveloped in fog.
The oval disturbance in the layer of altocumulus clouds in this photograph is a relatively rare phenomenon called a fallstreak hole or hole punch cloud.
These altocumulus clouds are formed from super-cooled water droplets many times smaller than a raindrop. The droplets are in a liquid state even though the temperature is well below freezing. When disturbed by an aircraft passing through the layer the droplets freeze and precipitate out of the cloud as virga. This and other processes create the hole.
The photo was taken on Saturday, January 21, 2017 at 2:23 p.m. near the Las Virgenes trailhead of Upper Las Virgenes Canyon Open Space Preserve. The hole was well south of the area.
Not since the beginning of the drought has Downtown Los Angeles experienced such a wet December. As of December 31, 2016:
• December rainfall was 2.22 inches above the monthly normal of 2.33 inches.
• The 4.55 inches of rain recorded was the wettest December since December 2010 and the most for any month since January 2010.
Since the Rain Year began July 1, 5.95 inches of rain has fallen at Downtown Los Angeles (USC). This is 1.63 inches above the normal July-December rainfall of 4.32 inches. It is the best start to the Rain Year (Jul 1-Jun 30) and Water Year (Oct 1-Sep 30) since 2010.
The photograph of Century City and Downtown was taken from Temescal Ridge while doing the Will Rogers – Temescal Canyon loop from the End of Reseda Saturday (December 24). According to NWS records Downtown Los Angeles recorded 2.32 inches of rain from December 21 to December 24..
On my run today (Tuesday), the leading edge of the cloud shield associated with a cut-off upper level low southwest of the Los Angeles began to move into the area.
Systems such as this are notoriously difficult to forecast and computer models (and forecasters) often disagree. In this case the wetter solution won the day with a half-inch of rainfall being recorded at Downtown Los Angeles (USC) Wednesday evening.
The storm increased December’s rainfall total in Los Angeles to 2.26 inches — about 0.88 inch above normal for the month.