Fall is here, and it is the beginning of two converging seasons in San Diego; the not-so-rainy season and the increasingly intense fire season. The official water year ranges from October 1 to September 30 and in 2017 the Lindbergh Field station received 3.34 inches of precipitation, with the highest rainfall in January (1.78 inches). This year, October brought hurricane Rosa, followed by tropical storm Sergio in mid-October. Both storms brought much needed rainfall to the San Diego area with a reported 0.57 inches from October 1 through 14. More great news is that NOAA has forecasted precipitation to be slightly above average in southern California through the end of the year!
These early, wet storms may give an extra boost to our San Diego fall blooming plants. Fall does not compete with the blooms seen in the spring, but blooms can still be found in the native landscape now. Several fall blooming plants are easy to find with a walk at the beach or a local trail. Common fall bloomers include the small, white star flower of Parry’s jepsonia (Jepsonia parryi), fluffy tufts of mulefat and coyote bush blooms (Baccharis spp.), and pale purple of the milk asters (Stephanomeria spp.). There are even some rare plants that are now in bloom like the bright yellow flower of Palmer’s goldenbush (Ericameria palmeri var. palmeri), the ruby bloom on Coulter’s saltbush (Atriplex coulteri), and the pearly blooms of white rabbit tobacco (Pseudognaphalium leucocephalum).
With October’s early, wet storms powering these fall blooms, also comes the Santa Ana winds blowing at 20 to 30 miles per hour and gusts exceeding 35 miles per hour. These strong, gusty winds paired with humidity lower than 10 percent often trigger red flag warnings throughout San Diego. These weather conditions lend to extreme fire conditions where temperatures often spike, fuel loads become extremely dry, and the chance of fire spreading once ignited is extreme. Unfortunately, the Santa Ana winds increase fire risk throughout the year and the outcome of these conditions is all too well known to the residents of California.
The big splash of rainfall early in the season, followed by dry, warm Santa Ana winds might cause a bit of confusion for our San Diego Flora. I am hoping the outcome will be prolonged blooms this fall!
For more information on fire safety in your neighborhood go to http://www.readysandiego.org/wildfire-hazard-map/
NOAA climate prediction center and the Climate Station Precipitation Summary were referenced for this article.
The photo of Jepsonia parryi was retrieved on 10/16/2018 from CalFlora and was originally provided by Keir Morse.
Shelley Lawrence