Much-diminished pool on Las Virgenes Creek on September 11, 2024, the day before the 4.7 Malibu earthquake.
It was very odd. After persisting in Upper Las Virgenes Canyon for 18 months, the pool on Las Virgenes Creek had unexpectedly receded.
When I’d run past the pool on September 6, it had been full. Just five days later — the day before the 4.7 Malibu earthquake — it had shrunk to a small puddle.
Pool on Las Virgenes Creek five days after 4.7 Malibu earthquake.
The earthquake occurred on September 12, 2024, at 07:28:21 PDT. That afternoon I ran out to Upper Las Virgenes Canyon and checked the pool again. It was already refilling. Five days later it was nearly back to its normal level.
Was the change in the pool level a precursor to the Malibu earthquake?
The pool is about 11 miles from the earthquake’s epicenter. Water level changes in wells miles from an event have preceded earthquakes similar in size to the Malibu quake. It’s something to wonder about.
This is the largest Southern Pacific Rattlesnake track I’ve seen in 20+ years of running at Upper Las Virgenes Canyon Open Space Preserve (Ahmanson Ranch) — or anywhere else.
An unusual amount of annual precipitation not only increases plant populations and growth, it can spawn the growth of plants not usually seen in an area.
On a recent run at Ahmanson, a glimpse of bright yellow along the trail caught my eye. I stopped to take a look and was surprised to find it was a yellow lupine — a variety of valley lupine (Lupinus microcarpus) not usually seen at Ahmanson Ranch.
Radially symmetric whorls of valley lupine flowers. Click for larger image.
Running south in upper Las Virgenes Canyon, I’d passed the connector to Cheeseboro Canyon and was nearing Las Virgenes Creek. Before reaching the creek, I turned left off the main road onto a path that has a log bridge across the creek.
As I stepped onto the berm at the edge of the road, I caught a glimpse of something small and furry moving at my feet. I stopped and stepped back.
That’s when the vole poked its head from a burrow. I could almost see it squinting as it assessed whether or not I was a threat. Deciding to continue foraging, it emerged from the hole as far as it dared, and worked to free a small clump of grass at the margin of the burrow. Mission accomplished, in a flash of fur it returned to its burrow.
Following are some notes and photos from runs in Upper Las Virgenes Canyon Open Space Preserve (Ahmanson Ranch) during March 2024. Spring is here! The hills are green, goldfields and other wildflowers are blooming, and Las Virgenes Creek is flowing.
Goldfields and Other Wildflowers
The first goldfields (Lasthenia gracilis) of 2024 began to bloom on Lasky Mesa at the end of February. Now, bright yellow patches of these “belly” flowers are scattered across the mesa, adding a brush of color to the roads and trails of Ahmanson Ranch. The cheery flowers usually disappear with the first spell of hot and dry weather. Looking ahead, more rain and cool weather are forecast Easter weekend, and extended temperature outlooks are mixed. Hopefully, the goldfields will be around for a few more weeks.
Catalina mariposa lily. Click to enlarge.
Some other wildflowers are also blooming. Blue Dicks usually flourish following a wet Winter, but this March are less widespread than usual. Red maids are also less numerous than normal and their flowers somewhat smaller. The elegant white flowers of Catalina mariposa lily are just starting to bloom.
After losing their leaves in December, the Valley Oaks at Ahmanson are now budding and sprouting. Some trees already have new leaves, while others are still bare-limbed. The period valley oaks are without leaves varies from year to year depending on rainfall, temperature, sunshine, and other factors.
Profuse rainfall is a two-edged sword. It revitalizes the ecosystem, turns the hills green, recharges the creeks, preserves the trees, produces wildflowers and more. But it can also be problematic — triggering slides, washing out and damaging trails, and promoting plant growth that chokes trails and increases the fire hazard.
At the moment, the roads and trails at Ahmanson are a bit rougher than normal, particularly in East Las Virgenes Canyon. Use and drier weather will gradually smooth out the ruts and rugosities, but we’re going to be picking foxtails from our socks for some time to come.
I sometimes stretch at the info kiosk at the Victory trailhead before running. Today, as I placed my hands against one of the kiosk posts and started to stretch, I glanced down. Disturbingly close to my feet was a small snake. Adrenaline flowing, I checked the head and tail and then checked them again. I stepped back and began to breathe. It was a gopher snake. But it could have just as easily been a rattlesnake. In fact, later on that run, I encountered a baby rattlesnake. That day and the next (March 20 and 21), I saw a total of four gopher snakes and two Southern Pacific rattlesnakes.
