The inflorescence of Canyon Liveforever (prob. Dudleya cymosa).
From a run at Sage Ranch Park on June 2, 2006.
Related post: Chalk Liveforever.
Category Archives: nature
A La Nina During an El Nino?
Sporadic rain in the Los Angeles area has finally produced a little green in local open space areas. Here, along the margins of the “main drag” in Upper Las Virgenes Canyon Open Space Preserve (formerly Ahmanson Ranch).
As of today, (preliminary) NWS climate data indicates Downtown Los Angeles (USC) has recorded 1.92 inches of rain since July 1. This is 7.31 inches below normal. Leafing back through weather service data prior to July 1, this is the total rainfall recorded since May 22, 2006 – a period of nearly nine months.
What happened to our El Nino rains? According to NWS scientist Ed Berry, “the global circulation has been generally La-Nina like since about late November.” This is despite an El Nino event that peaked in November or December, and persisted at moderate strength into January. See his blog Atmospheric Insights for the technical details.
A period of unsettled – possibly showery – weather is forecast for the Los Angeles area beginning Sunday evening and continuing pretty much through the week. At the moment* the best chance for measurable rain appears to be on Monday and Thursday. We’ll see!
*Updated Saturday, February 17, at about 11:00 a.m.
Related posts: The Color of Rain, El Nino Drought, Sunset Snow Shower, Rainy Morning on Rocky Peak Road.
Winter Oak on Laskey Mesa
From a run in Upper Las Virgenes Canyon Open Space Preserve (formerly Ahmanson Ranch).
Sunset Snow Shower
When I heard the news reports of snow in the Santa Monica Mountains along Kanan-Dume road near Malibu, I hoped to find a little snow or hail up at Sage Ranch Park on my afternoon run.
The isolated snow showers, hail and sleet were produced by convective cells that developed as a result of instability associated with a passing upper level low. Some of these cells also generated some lightning and thunder.
There was no snow on the ground at Sage Ranch, but the low angle rays of the setting sun did highlight a snow shower over the Rocky Peak Park area. In March of last year there was snow at Sage Ranch and Rocky Peak.
Related posts: Chumash Trail Snow, Oat Mountain Snow, San Fernando Valley from Rocky Peak.
Twiggy Wreath Plant?
An ant forages among the florets of a wreath plant.
I’ve run past wreath plants thousands of times in the chaparral of local open space areas. At a glance, the nondescript wiry brown plant isn’t very appealing. But it’s one of a few plants you’ll see blooming in the chaparral in the Fall, so on a run this last November I took a closer look. This revealed a lavender-tinged composite flower that is anything but mundane. And, as I was to discover, a case of probable mistaken identity, and an example of one of the ways new species occur.
Three field guides in my library identify the plant pictured above as Twiggy Wreath Plant (Stephanomeria virgata). But, as discussed by Tom Chester, there is some confusion regarding it’s characteristics and identity. It could be the case that many Southern California plants previously identified as S. virgata may actually be San Diego Wreath Plant (S. diegensis), including those in the Santa Monica Mountains.
The plants are very similar, but according to the identification key for the genus Stephanomeria in the Jepson Manual can be distinguished by a groove along the length of a seed (achene). This isn’t something easily done in the field. The achenes are so tiny that they are best seen in a strong loupe or a low power microscope. Wayne’s World Volume 9 (Number 3) Fall 2000 has some photographs of the achenes and groove.
So why are S. virgata and S. diegensis so similar? The genetic relationship of various members of the genus Stephanomeria has been researched and it appears likely that S. diegensis is a relatively recent species that resulted from a natural cross of S. exigua and S. virgata.
The photograph of the foraging ant was taken on a run at Sage Ranch on November 5, 2006. Based on examination of some achenes from wreath plants in the area, the plant is probably Stephanomeria diegensis.
Technical papers:
Genetic Evidence for the Hybrid Origin of the Diploid Plant Stephanomeria diegensis
G. P. Gallez, L. D. Gottlieb
Evolution, Vol. 36, No. 6 (Nov., 1982), pp. 1158-1167
Phylogeny of Stephanomeria and related genera (compositae–lactuceae) based on analysis of 18S–26S nuclear rDNA ITS and ETS sequences
Joongku Lee, Bruce G. Baldwin and L. D. Gottlieb
American Journal of Botany. 2002;89:160-168
El Nino Drought
The open space areas in which I run would normally be lush and green by this time of year, particularly when there is an El Niño. But in the past 231 days (including today) the official weather station for Los Angeles has recorded only 1.31 inches of rain, and the hills remain a dank sun bleached gray-brown.
As mentioned in my post The Color of Rain, usually when there’s an El Niño, wet Winter weather can be expected to occur in Southern California. This year’s El Nino was late to develop, became stronger than expected, and may have already peaked.
Warm water in the tropical western Pacific contributes to the development of an El Niño, and studies show this pool of warm water has been increasing in temperature, perhaps increasing the strength and frequency of El Nino’s. The quirkiness of this year’s El Niño may be related to these changes.
Is any relief to our drought in sight? Not in the short term. A system forecast to affect the Los Angeles area Thursday and Friday will likely result in cooler temperatures and more wind, but little – if any – rain*.
In his blog Atmospheric Insights, NWS scientist Ed Berry discusses the possibility of a high impact precipitation event developing in California later this January*. A flow pattern with a strong lower latitude jet stream is typically associated with El Niño induced precipitation events in California.
California weather this rain season will be closely monitored by scientists participating in NOAA’s Hydrometeorological Testbed (HMT) Program. This program is “aimed at accelerating the infusion of new technologies, models, and scientific results from the research community into daily forecasting operations of the National Weather Service (NWS) and its River Forecast Centers (RFCs).”
The photograph of the dry grasslands in the Simi Hills west of Rocketdyne was taken on a run to the northern boundary of the Upper Las Virgenes Open Space Preserve on December 24, 2006. The photograph of the green hills in the Ahmanson Ranch area of the Upper Las Virgenes Open Space Preserve is from a run on January 18, 2005.
*Updated 01/10/07. Today’s runs of the computer weather models are projecting from about 0.1 inch to 0.25 inch of rain from this system at Los Angeles. Also, see the January 10 update to Ed Berry’s Atmospheric Insights blog. Consolidation of the Pacific jet now appears unlikely, so we may not see typical El Nino impacts developing in California this month. There may be rain, but perhaps not as a result of a classic El Nino pattern. We’ll see!