Following four rainfall years in which Downtown Los Angeles (USC) has cumulatively recorded less than half of normal rainfall and accrued a precipitation deficit of more than 30 inches, many of the valley oaks at Ahmanson Ranch (Upper Las Virgenes Open Space Preserve) are drought stressed.
The most obvious signs of drought stress in valley oaks and many other plants are a reduced number of leaves and reduced leaf size. In severely stressed valley oaks the foliage has the appearance of a tree that is recovering from a wildfire.
At Ahmanson the degree of stress varies widely from tree to tree. The “TV tree,” an aesthetically-shaped and often-photographed valley oak on the west side of Lasky Mesa appears to be showing a higher than average level of stress.
Valley oaks and live oaks cohabit the oak savannas at Ahmanson Ranch, but live oaks appear to be more drought tolerant. The lone Blue Oak at Ahmanson seems to be doing OK and has at least as much foliage as it did last year at the same time.
Even with a wind shell and multiple layers the gusts of wind were sharp-edged and penetrating. The weather was spectacular, but it was very windy and very cold.
My run on the PCT had started at Islip Saddle in the San Gabriel Mountains. At 8:00 am the temperature at 6593′ had been about 35 degrees. The north wind funneling through the saddle had roared through the pines, buffeting their stout limbs and telling me to put on every scrap of warm clothing I had in my pack.
The broad canyon of the South Fork seemed to act as a wind tunnel — drawing the wind from the high desert into and over the crest. Even with a gloved hand it took only a couple of minutes before my camera became too cold to hold.
I was on my way to Mt. Baden-Powell and nearly up to Mt. Hawkins. With every stride up the mountain the temperature had dropped. Father Frost had frozen the landscape and me along with it.
Had it really been just a week ago when I had broiled in 90+ degree temps on the south-facing sections of trail on the Leona Divide 50M course?
Well, maybe not Shangri-La, but a Lost World kind of morning on the Calabasas Peak fire road segment of the Secret Trail.
Calabasas Peak fire road traverses the rock formations on the left, descending to Stunt Road. At Stunt the route continues up the Stunt High Trail to the Backbone Trail. Here you can do an optional out and back to Saddle Peak, shrouded in clouds in this photo, or turn west on the Backbone Trail and continue mostly downhill to Piuma Road near Malibu Canyon Road. Malibu Canyon is in the distance on the right in the photo.
Although we are still experiencing a record-breaking drought, this rain season did provide a little short term relief to plants and wildlife. Compared to last year rainfall is up 27% at Los Angeles, 39% at Santa Barbara, 57% at LAX and 63% at Camarillo/Oxnard according to NWS data.
The increase in rainy season precipitation dramatically increased plant growth, the abundance of wildflowers, and temporarily increased the availability of key resources to wildlife.
Another thing it seems to have increased is the number of rattlesnakes. Over the past two years I have seen maybe two rattlesnakes total on my runs in the Santa Monica Mountains, San Gabriel Mountains, and in the Big Bear area and on San Gorgonio Mountain. In the Ahmanson Ranch – Cheeseboro area I’ve seen none.
With the increase in rainfall this season that has changed. The title photo was taken on the Leona Divide 50/50 course March 28. That day I encountered two rattlesnakes and talked to a runner that had seen three on the course the previous weekend. From March 26 to April 2 I encountered rattlesnakes on three out of four runs. Two of those were at Ahmanson and it seemed everyone I talked to on the trail was seeing rattlesnakes.
There has also been an increase in the number of encounters with non-venomous snakes as well. I’ve seen a number of gopher snakes and a California striped racer. Friends have mentioned seeing a ring-necked snake and California kingsnake.
Since the weather has cooled I haven’t encountered any rattlesnakes, but have seen their tracks. When I run, especially on single-track trails, my snake radar is on and I’m definitely on the lookout for the hard-to-see beasts.
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Following last year’s drought-induced hiatus goldfields are once again blooming in profusion on Lasky Mesa. The little yellow “belly flowers” tend to grow in low spots and along paths where rain water pools.
Race director Nancy Shura-Dervin picked a great year, and as it looks now, a great weekend for the inaugural running of the Ahmanson 12K Trails event.
The hills are lush and green; wildflowers are in bloom; valley oaks are sprouting fresh green leaves; and it’s looking like race day may be one of those “gotta run” kind of days.
According to today’s NWS forecast the area will see dry and warmer weather beginning Tuesday and continuing through race day. While there could be a remnant puddle here or there, four days will be plenty of time for the dirt roads to (mostly) dry out. The Cheeseboro RAWS automated weather station can be used to get an idea of the current weather in the vicinity of the race course.
Over the past 10 years I’ve logged approximately 6000 miles at Ahmanson Ranch (now Upper Las Virgenes Canyon Open Space Preserve) and the loop Nancy has selected for the course is a variation of a favorite.
Lasky Mesa has long been used to shoot movies, television, commercials, music videos, and even Internet games. Its wildland character and expansive views bely its urban location. For a few weeks one summer the Mission Impossible III bridge was a Lasky Mesa landmark. The aesthetically-shaped valley oak at the west end of Lasky Mesa is a favorite of production companies and I’ve spotted it in more than one commercial.
The Ahmanson 12K should be an outstanding event on an excellent course in conditions we haven’t seen at Ahmanson in several years.
Instability associated with an upper low resulted in some pop-up showers and thunderstorms today.
As I ran up the Chumash Trail on the east side of the Simi Valley I kept a close eye on a cell that developed near Ladyface in the Agoura Hills. That cell didn’t track as much to the east as I thought it might, but other cells were developing to the east and south of Rocky Peak and Santa Susana Pass area and at one point I heard the rumble of thunder.
As it worked out, I only had a few sprinkles on the run, but drove home in the rain!
The rising sun illuminates a translucent layer of cloud trapped by a shallow inversion in the San Fernando Valley. The mid-level clouds above are associated with a system that brought heavy rain to much of California, but would only produce showers in the Los Angeles area.