From a run this May in Upper Las Virgenes Canyon Open Space Preserve (Ahmanson Ranch).
Normal rainfall for May at Downtown Los Angeles (USC) is 0.26 inch. This year Los Angeles recorded 0.81 inch in May, according to the NWS .
It was definitely wet and cool! Nineteen days were partly cloudy to cloudy. Ten days recorded at least a trace of rain. The average high was 70 degrees.
Oddly, during our recent drought, above normal May rainfall totals were recorded in 2011 (0.45 inch), 2013 (0.71 inch), and 2015 (0.93 inch). The most rainfall recorded in May at Los Angeles was 3.57 inches in 1921.
I’d done a long run the day before in Pt. Mugu State Park, so the plan for this morning was to do a short run and check out the Woolsey Fire impacts between Century Lake and the M*A*S*H site in Malibu Creek State Park.
In addition to checking the condition of the coast live oaks and other native trees, I was curious to see how the coast redwoods along the Forest Trail had fared. These trees were planted nearly a century ago and in recent years have struggled with the drought. Had they survived the fire?
It had been about a year since I had checked on the redwoods. The good news is that a few of them still appear to be viable. The bottom limbs on some of the trees were scorched, but I think they will be OK. Of the 16 or so redwoods, about five have died, about five are in poor shape, and five or six appear to be OK. There is one young naturally occurring tree that was severely scorched and may not survive. We’ll just have to see.
While there was some damage to the M*A*S*H site, the picnic tables, ambulance, and signpost made it through the fire. Some repairs will be necessary.
I was supposed to turn around at the M*A*S*H site, but you know how that goes. I wanted to see “just a little” of the Bulldog climb… and a little more… and a little more. I finally ran out of time about 2.5 miles up Bulldog Mtwy and headed back.
Even when you expect it, it is sobering to see areas of high soil burn severity. Thirty-six years of robust chaparral growth were just… gone. Also startling were the stream flows and debris flows that resulted from “only” about 1.5 – 2.0 inches of rainfall in early December. An atmospheric river event of the magnitude that caused the Malibu Creek flooding in February 2017 would be catastrophic.
A lot of work had been done on Bulldog Mtwy. It had been repaired and graded. Where there was still brush and trees along the road the branches had been trimmed!
As of March 1, Downtown Los Angeles had recorded only 1.99 inches rain over the past eight months. Most of that was recorded in one storm in early January. It was the second driest July 1 – February 28 on record.
Following the January storm, temperatures warmed up and stayed relatively warm for much of the next 30 days. In the West San Fernando Valley the high temperature hit 89 °F at Pierce College on February 4, and was over 80 °F for 12 consecutive days. Some plants (and some rattlesnakes) responded as if it was Spring.
In mid February Winter returned, with cool daytime temperatures and cold nights. There were Frost and Freeze Warnings on several nights.
In March the ridiculously resilient ridge of high pressure over the West Coast finally relented, resulting in above normal rainfall. It took awhile, but the March rain and April sun eventually produced an assortment of wildflowers.
Even though rainfall in the Los Angeles area is way below average this rain season, some plants along our local trails — such as this poison oak — are flourishing.
The growth of plants is dependent on a mind-boggling mix of interrelated factors. Maybe it was the rain in January in combination with the unseasonably warm weather in January and February. Or maybe there was some carryover in vitality from last year’s wet rain season. Or maybe it was something else. Whatever the case, poison oak in the Santa Monica Mountains seems to be doing very well this year!
The title photo is of poison oak along the Rogers Road segment of the Backbone Trail. It was taken March 10, 2018. Watch for overhanging branches!
Once again Southern California is facing another very dry rain year. Since July 1, Downtown Los Angeles (USC) has recorded only 1.97 inches of rain. This is more than 8.5 inches below normal.
At this point it appears likely the rainfall recorded at Los Angeles from July 1 – February 28 will be the second driest for that period on record. If we don’t see some significant rain in March, we could be contending with 2006-2007 for the driest rain year on record.
Several weather models have been advertising a change to a wetter weather pattern for the West Coast and Southern California. At one point the ECMWF was forecasting several inches of rain in the Los Angeles area around March 1-2. This morning’s ECMWF run was far more stingy with the wet stuff, and precipitation completely disappeared from the GFS forecast for that period.
Never fear, these forecasts will likely change again. Model skill more than a few days out is very poor. Next week we should have a better idea if the pattern change is real, or just more model hype.
Update March 1, 2018. With only 1.99 inch of rain from July 1 to February 28, Downtown Los Angeles (USC) did end February with the second driest rain year to date. Depending on whether 1911-1912 is included in the ranking, the water year to-date, beginning October 1, is either the second or third most dry on record. Now all eyes turn to the storm that is forecast to move into the Los Angeles area this evening. This morning the CNRFC 72 hr. QPF for the Los Angeles area ranges from around 0.75 – 1.0 inch in the basin and valleys to around 1.5 – 1.75 inches in the mountains. Higher totals are forecast in the Ventura and Santa Barbara areas. Check with the NWS Forecast Office Los Angeles for the latest weather forecasts, advisories and warnings.