Acton Thunderstorm

Developing thunderstorm over the Acton area, north of Los Angeles, from Ahmanson Ranch near the Los Angeles County - Ventura County border.

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.

Southern California Thunderstorms an El Nino Calling Card?

Valley oak on Lasky Mesa, with a line of thunderstorms in the distance.

Off to the south, I heard the distant rumble of thunder. The developing line of thunderstorms had swept through the West Valley about an hour before I began my run at Ahmanson Ranch.

Unusual weather for June. Not so much that there were thunderstorms, but that the thunderstorms were in part the result of an unseasonably strong jet embedded in the base of an upper level low.

It’s a bit of a stretch, but an argument could be made that these storms were a calling card of an increasingly energetic atmosphere, and a developing El Niño.

Several factors point to an increased probability of El Niño conditions developing over the next few months. Among them, Equatorial Pacific SSTs have increased, and the subsurface heat content is the highest it’s been since the El Niño of 2006-07.

But as the short-lived 2006-07 El Niño event demonstrates, an El Niño is more than just warm Pacific equatorial SSTs. Through complex forcing and feedback mechanisms, the atmosphere and oceans have to cooperate on a global scale. Generally speaking the atmosphere speeds up when there is an El Niño, and slows down during a La Nina.

And it looks like the atmosphere may be speeding up. Orbits of the Global Wind Oscillation, a measure of atmospheric momentum, have been shifting upward, in the direction of more energetic values usually associated with an El Niño.

But an El Niño is not a done deal. The climate system is just leaning in that direction. As climate scientist Klaus Wolter has pointed out, in a similar situation in 1973-1975, the climate fell back into a La Niña for another year. At this point it appears we may be diverging from that analog case. We’ll see!

Update June 6, 2009. The April-May Multivariate ENSO Index (MEI) value, released today, has increased by 0.54 to +0.34. As discussed by MEI originator, Klaus Wolter, the 3-month rise of the MEI since January-February is the 4th highest on record for this time of year, exceeded only by the strong Niño of 1997. According to Dr. Wolter, if next month’s MEI rank is at least the same as this month (37th), “it would be unprecedented for it to drop below that high-neutral ENSO-phase range by the end of 2009, virtually excluding a return to La Niña, based on the MEI record since 1950.”

Related links: ENSO Diagnostic Discussion, ENSO Wrap-Up

Thunderstorm

Developing cumulonimbus near Mt. Abel

Developing Cumulonimbus Near Mt. Abel

Saturday, Pierce College in Woodland Hills set an all-time record high temperature of 119°F. Following a preliminary review, a NWS forecaster said this was probably the highest temperature ever recorded at an official weather station in Los Angeles County.

To escape this oppressive heat, and avoid the scorching temperatures of last week’s long run, my intent was to get to the highest elevation possible, as early as possible, and stay as cool as possible. At an elevation of about 8400′, the Mt. Pinos Chula Vista trailhead is nearly 2000′ higher than Islip Saddle in the San Gabriel Mountains, and is usually a good choice for a run on a warm day.


San Gabriel beardtongue (Penstemon labrosus) near Sheep Camp.
A little after 7:30 a.m., under nearly cloudless skies, I jogged out of the Mt. Pinos parking lot reveling in the cool mountain air. I didn’t have a specific route in mind, but thought I would probably do a longer variation of the Mt. Pinos to Mt. Abel run described in my Vincent Tumamait Trail post. Energized by the cool temperature, it didn’t take long to work up and over the summits of Mt. Pinos (8831′) and Sawmill Mountain (8816′), and then down the North Fork Trail to the spring at Sheep Camp (8200′).

Surrounded by the greens of the spring, and the yellows and reds of wildflowers, I gulped cold water, and thought about where to run. A sign at the “T” with the Tumamait Trail listed the distance to “Lily Meadows Camp” as 3 miles. I hadn’t been on that section of North Fork trail since preparing to run the Inca Trail in 2003.

Deciding to continue down to Lily Meadows Camp, I crossed over the spring and followed the little used, pine needle covered trail southeast along the hillside. The trail dropped steeply along a rounded ridge, where mountain quail fretted among the manzanita and fallen trees, and the minty fragrance of Pennyroyal drifted up from the margins of the trail. Quicly losing elevation, I reminded myself that whatever I ran down, I would have to go back up.

After about a mile and a half, the path switchbacked down to the North Fork of Lockwood Creek. Here, the grade lessened and long stretches of nearly perfect trail running led to Lily Meadows Camp (6250′). Old growth Jeffry pines towered above the camp, and a Monarch butterfly flittered about on a current of air. The pleasant, Sierra-like environment was a welcome change from the 100 degree heat of the previous week!


The first cloud!
An 1800′ climb and an hour later, I’m back at Sheep Camp, refilling my Camelbak®. Suddenly a shadow sweeps over the forest, and a small cloud – the first cloud – looms overhead. It’s just after 11:00 a.m., and the heat of the day has triggered some cloud development. After taking a few photos and eating a Clif® Bar, I decide I better get going, and jog up to the junction with the Tumamait Trail.

Reaching the trail junction at about 11:30 a.m., what had been a single tattered cloud in the sky is now several, and my “inner voice” of experience says, “Turn right, you can be back to the car in under an hour!” But it has been such an enjoyable day, and there aren’t that many clouds… I turn left towards Mt. Abel.

At first, shadow and sun play tag among the trees and I join in, chasing the clouds down the twisting and turning trail. The partly cloudy skies are postcard perfect, and I wonder if my concerns are ill-founded. But as the superb downhill segment transitions to up, a gray gloom invades the forest. At Mt. Abel Road, it’s noon. Rationalizing that the extra minutes required to scramble up to Mt. Abel’s summit won’t hurt, I cross the road and head up the steep slope.


The sun breaks through the darkening sky, illuminating the face of Grouse Mountain.
Seven minutes later, I’m back at Mt. Abel road. For a brief moment, a narrow shaft of sun breaks through the darkening sky, illuminating the face of Grouse Mountain. It washes across the slopes of the mountain, and then suddenly all is in shadow. At that instant, I know I’m in a race that I cannot win.

A quarter mile down the trail, the first cold drops of rain dampen my bare legs, and in another quarter mile, there is a rumble of thunder to the north, and then another rumble behind me. Part way up Grouse Mountain, there is a flash, and then directly above me an immediate ear-splitting, crackling clap of thunder. From the first few clouds to the first lightning has taken little more than an hour!

In an astonishingly short period of time, the rain, lightning and thunder grow in magnitude. Flash – boom! Flash – boom! The storm engulfs me as it grows in intensity. In the expanded microseconds that follow each lightning flash, I  breathe a sigh of relief that I’m not struck, and then bodily recoil from the immediate and overwhelming power of the crashing thunder.

Cresting the shoulder of Grouse Mountain, I think back to a storm in the San Gabriels, where instead of striking an obvious ridge, a bolt of lightning struck a nondescript tree on the slopes below. There is no place to hide from this monster. I adopt a tactic of almost sprinting through open areas, past tall trees, and when the electric motor smell of ozone fills the air. In areas that seem a little safer, I slow my pace.

At the top of another long climb, near the North Fork trail junction, I’m surprised to see a group of 8 or 9 hikers huddled under a pine tree. They are probably surprised to see someone running along the hilltops. From the first rumble of thunder, I’ve been considering whether hunkering down in the forest off the ridge might be a better strategy. If I had my shell pants, or my runner’s emergency bivi sack (a plastic trash bag), it might be. But wearing just my rain shell, a short-sleeve synthetic top and running shorts, I’m under-dressed for this get together.

Off to the east, in the direction of Mt. Pinos, the sky seems lighter. Maybe the wind is shifting the cells to the west and north. I have no idea how long this thing is going to last, and the pounding rain and gusty winds are sleety cold. I don’t want to stop. Not at all sure it is the better choice, I wish the hikers the best, and continue up the trail toward Sawmill Mountain.

The storm, and my emotions, wax and wane in a recognizable, but hard to define pattern. Periods of awe, elation and fear cycle with the storm. It has only been 30 minutes since the rain and thunder began, but in my distorted world, it might have been 30 hours. The steady rain has flooded the trail, and I feel like I am crossing a never ending creek.


Hurried photo near the top of Sawmill Mountain, when the storm was nearing peak intensity.
As I near the summit plateau of Sawmill Mountain, erratic gusts of wind tear at the trees. Then suddenly, as if a dam has broken, a deluge of lightning, thunder, rain and hail spills from the sky. It is the most intense rain I have ever experienced. A pounding rain, thick with hail, driven by a downburst of wind and gravity. Torrents of water cascade down the trail. It is ferocious.

Running through the maelstrom across the plateau, ahead I can see the point where the trail drops off the summit, and descends to a saddle. I just have to get there. Lightning flashes, and thunder booms behind me. My feet are numbed and cold, and I wonder how water on the trail can be calf deep.  Reaching the shoulder of the mountain, I start to descend. From time to time I get a glimpse of Mt. Pinos, and I can see a little smudge of blue under the dark clouds over the summit. As I descend toward the saddle, the intensity of the storm seems to be diminishing. There is still lightning, thunder and rain, but for a moment the focus of the storm seems to be shifting elsewhere. I take a deep breath, and debate what I’m going to do about getting over the exposed summit of Mt. Pinos.


Looking back at ridge on Sawmill Mountain from shoulder of Mt. Pinos.
There are still two groups of active cells. The main thunderstorm complex seems to be behind me, toward Mt. Abel; but there is also an active group of cells just north of Mt. Pinos. While I’ve seen no lightning strike the summit of Mt. Pinos, it is almost a certainty. I decide to work up the switchbacks toward the summit, continuing my tactic of minimizing my time in areas that are exposed. The rain has nearly stopped, and I haven’t smelled ozone since on Sawmill Mountain, but some sections of the trail are frighteningly exposed. Working up to the highest point that appears to offer some protection, I pause and listen. The timing may be right. The thunderstorm activity seems to be in a down cycle.

I leave my alcove. In seconds I’ve rounded a rocky rib of the peak, and am suddenly the tallest and most linear object on its bare shoulder. Thunder rumbles off to the north, a reminder I don’t need. Heart pounding, I’ve already pushed the pace as much as the grade, elevation, and my body will allow, and now there is nothing for me to do but run.

It is not a relief to reach the summit. I see a bolt of lightning strike to the northeast, near a radio tower less than a quarter mile away. Partially hidden from view, I can’t tell if the lightning struck the tower, or a ridge beyond. It doesn’t matter. I have to get off the summit.


Mariposa lily (Calochortus invenustus) west of Mt. Pinos.
Running along the road from the observation point, I’m nervous about going in the direction of the relay tower, and the last lightning strike. I know the road will soon turn downhill, but as hard as I am running, I don’t seem to be getting anywhere. Finally, I see, and then round the turn. Another 50 yards, and for the moment I’m safe. A dash across one meadow, and then another, and the main danger is past.

To the east, I see more blue sky, and broken clouds. Continuing to descend, I hear a group of Chickadees chattering in a nearby tree. They sound happy. So am I.

Here’s a Google Earth image and Google Earth KMZ file of a GPS trace of my route.

Epilogue: According to the American Meteorological Society, lightning kills more people per year on average than hurricanes and tornadoes combined. For more information regarding lightning safety, please see the National Weather Service Lightning Safety page. Here’s what the thunderstorm looked like on radar.

(The title photograph is of a developing cumulonimbus near Mt. Abel. It was taken on a run at Sage Ranch on July, 19, 2006.)

Running Between Raindrops: Chumash Trailhead to Rocky Peak

Rain in the San Fernando Valley from Rocky Peak. March 12, 2021.
Rain in the San Fernando Valley from Rocky Peak

Was that thunder? I warily eyed the dark clouds over the mountains and pondered the situation.

I was about halfway to the top of the Chumash Trail and was planning to run along the crest to Rocky Peak. The run had started in short sleeves and sunshine, but it was pretty obvious that wasn’t going to last.

Chumash Trail about a mile from the trailhead
Chumash Trail about a mile from the trailhead

A cold upper-level low had brought badly needed rain to the area for the past two days. The low was moving off to the east, but there was still a chance of afternoon showers and maybe even a thunderstorm.

It was the “thunderstorm” part that I needed to pay attention to. I had enough gear to deal with a downpour and cooling temps, but electrical storms are no fun at all.

I decided to continue to the top of the Chumash Trail and reassess. As I worked up the trail, I pictured the counterclockwise circulation around the low, and how convective cells develop over the mountains and then dissipate as they drift south. The concern was that the cells don’t always dissipate.

Rocky Peak Road near Rocky Peak
Rocky Peak Road near Rocky Peak

It looked like things weren’t getting any better at the top of the Chumash Trail, but it wasn’t worse either. I hadn’t heard any thunder for a while, and most of the activity seemed to be a few miles to the west and east. Having been starved of stormy weather for much of the rain season, I turned right on Rocky Peak Road and headed south toward Rocky Peak.

The run from the Chumash Trailhead to Rocky Peak is a challenging mix of technical single-track trail and hilly fire road. There are wide-ranging views of Simi Valley & Simi Hills, the San Fernando Valley, Santa Monica Mountains, Ventura County mountains, and San Gabriel Mountains. On a clear day, the view can extend to the Channel Islands, Saddleback, and San Jacinto Peak.

NOAA radar mosaic Rocky Peak March 12, 2021.
NOAA radar mosaic at the time I was on Rocky Peak

The actual turnaround point for a run to “Rocky Peak” varies. Some like to turnaround at the high point of Rocky Peak Road that is near Rocky Peak. Most of the time, I turnaround at a viewpoint that is at the end of a spur trail that branches off from the high point of Rocky Peak Road. From time to time, it’s fun to hike over to Rocky Peak and scramble to the top. That’s a bit more involved and requires some route-finding.

I felt the first raindrops as I reached the high point on Rocky Peak Road and turned onto the spur trail that leads to the overlook. There was some increased development to the east, but it looked like there would be enough time to get over to Rocky Peak, take a couple of pics, and then head back.

Oat Mountain, shrouded by rain
Oat Mountain, shrouded by rain

I felt a little exposed on top of Rocky Peak. I hadn’t heard any thunder for the past hour, but a cell to the east was spouting heavy rain over the San Fernando Valley, which meant there was probably enough development to produce lightning. I took the title photo and a couple of others and hurriedly descended from the peak.

Back on Rock Peak Road, the sprinkles increased, and the showers became more steady as I ran north toward the Chumash Trail. Under the dark clouds, a raven perched on a large pinnacle cawed incessantly, either enjoying the rain or complaining about it. In the distance, a siren wailed down in the valley. It was cold, and I was very glad to have an extra shirt, sleeves, gloves and a light rain shell.

Mix of sun and rain on the Chumash Trail
Mix of sun and rain on the Chumash Trail.

As I began the descent of the Chumash Trail, the sun briefly broke through the clouds, reflecting brightly on the wet sandstone rocks. I breathed deeply, relishing the smell of the cleansed air and wet chaparral, and continued down the trail.

Here’s an interactive 3D terrain view of my GPS track. Over the run, the temperature sensor on my pack recorded a drop of about 30 degrees — from around 70°F at the start of the run to about 40°F when the showers began! Here’s what a NOAA Radar Mosaic looked like at the start of the run and when I was on Rocky Peak.

Related: Chumash Trail, Rocky Peak, Thunderstorm

San Gorgonio Mountain Snow Follow Up

Hiker working up the Sky High Trail on San Gorgonio Mountain in Southern California
Hiker on the Sky High Trail

One of the things I’d been curious to see when running the Kodiak 50K in mid-August was how the summit snow band on San Gorgonio Mountain was holding up. The answer turned out to be fairly well. Now, a few weeks later, I was back on Gorgonio, chugging up the South Fork Trail, and on my way to see if any snow remained on the mountain.

Runoff from thunderstorms during the week had left the trail rocky and rutted. From the views of the mountain I’d glimpsed from the trail, I wondered if the rain had also washed away any remaining patches of snow.

Snow band near the summit of San Gorgonio Mountain. September 7, 2019.
Snow band near the summit of San Gorgonio Mountain on September 7, 2019.

In addition to that question, I also want to follow up on my earlier “field checks” this Summer and see how much water there was in Dry Lake, and if any snow remained in the avalanche debris above Dry Lake.

I was about a quarter-mile from the Dry Lake – Dollar Lake junction at South Fork Meadows, making decent time, when I heard footsteps behind me. I stepped to the side so he could pass, and we talked as we worked up the trail. Kevin said he’d been climbing in the Sierra just about every weekend and was really well-acclimated.

I asked him what route he was doing to the summit, and he said the Dry Lake route. I told him I was doing the Dollar Lake Trail route up and the Dry Lake route down. He was clearly moving faster than me and said he was shooting for a time of 4:20 to the summit. I mentioned the Dollar Lake route was shorter and faster, and depending on the number of stops for photos, I expected to get to the summit in around 3:45. We talked about some Sierra peaks and being in the mountains, and after a couple of minutes, he began to pull away.

Trail runner at Dry Lake on San Gorgonio Mountain
Dry Lake on September 7, 2019.

The early morning temperature had been a little more chilly than my earlier trips up Gorgonio this Summer. I debated pulling on my sleeves, but by the time I was in the sun on the Dollar Lake Trail, the temperature had warmed to a comfortable 50-something — perfect for ascending the peak.

The summit of San Gorgonio was a very busy place when I arrived. I’d estimate 40-50 people were on or around the summit. Most were part of one huge group that had come up Vivian Creek.

The good news was part of the summit snow band had not melted. Wow! It was September 7, and there was still snow in Southern California!

Copernicus Sentinel satellite imagery of snow on San Gorgonio Mountain on August 27, 2019.

Kevin caught up to me on the descent of the Sky High Trail. We’d both made the summit within a couple of minutes of our projections, leaving little doubt that the Dollar Lake Trail is the fastest route to the summit from the South Fork Trailhead.

I didn’t see any snow remaining in the avalanche debris above Dry Lake. The lake itself was in great shape, and the streams at South Fork Meadows were flowing nearly as vigorously as they had been a month ago.

I’ve added a couple of photos from this trip to the San Gorgonio Mountain Snow, Avalanches and Glaciers slideshow.

Update November 26, 2019. A small amount of snow from the 2018-19 season has survived on San Gorgonio Mountain until the first persistent snow of the 2019-20 season! Copernicus Sentinel satellite imagery from November 17, 2019 showed small patches of snow in two areas. The first winter storm of the season brought snow to the mountains a couple days later, and more snow is expected over the Thanksgiving holidays.

Update October 21, 2019. Copernicus Sentinel satellite imagery from October 21, 2019 still showed a few very small patches of snow on San Gorgonio Mountain. One of the patches is at a surprisingly low elevation of about 10,360′.

Update September 18, 2019. Copernicus Sentinel satellite imagery from September 18, 2019 still showed a few small patches of snow on San Gorgonio Mountain.

Related post: San Gorgonio Mountain Snow, Avalanches and Glaciers