Toward the end of 1861, the “Noachian deluge of California Floods” occurred.
A series of storms produced nearly continuous rain that lasted through February 1862 over most of California. Los Angeles recorded nearly 36 inches of rain while Sonora in the Sierra Nevada foothills measured more than 100 inches!
By February 1862, the Sacramento and San Joaquin valleys became almost an inland sea stretching nearly 300 miles in length, forcing the state capital in Sacramento to move to San Francisco. Ironically, later in 1862 would mark the beginning of a horrific drought that continued through 1864.
Joy Fitzhugh, of the SLO County Farm Bureau wrote a fascinating story about 1860s drought that appears on the Farm Bureau’s website. According to the “Paso Robles 125th Anniversary Blog,” only 0.3 inch of rain fell in fall 1862, and “no rain fell until the fall of 1864.” It also stated that vaqueros drove starving cattle on Rancho Santa Rosa over the cliffs into the ocean “to put them out of their misery.”
Cal Poly history professor Dr. Daniel Krieger, who authors the “Times Past” column for the Sunday edition of The Tribune, wrote, “Virtually all of the herds of mission-bred cattle and sheep were destroyed. Visitors to the area remarked that the sun-bleached bones of dead cattle were strewn over every hill and gully. The late afternoon sun created an almost blinding effect, as its light was reflected from the chalk-white carcasses in El Portrero de San Luis Obispo, the old mission pasture, now the Cal Poly campus just north of town.”
However, without any continuous rain records, it’s difficult to know if this was the worst three-year drought seen. The earliest continuous rain records that I could find for our area are available at the Cal Poly Irrigation Training and Research Center website, which stretches back to 1870.
Nevertheless, these stories paint a frightful picture of the conditions at that time. So far, the last three rain seasons at Cal Poly had a total of 39.6 inches of rain, the second driest three-year period on record.
The driest three-year time frame occurred from 1958 through 1960, during which 38.8 inches of rain fell. Since 1870, no other three-year period is near these two.
Unlike 1958-1960, the current three-year drought has been warmer. In fact, so far this year is the warmest on record for California, running about 5 degrees warmer than average. The lack of rain combined with above normal temperatures has lowered vegetation moisture levels to record low levels in San Luis Obispo County, according to Cal Fire.
Due to these vegetation moisture levels, I’ve received numerous emails and phone calls about the condition of our oaks. I reached out to Dr. Bill Tietje, who is an area natural resources specialist with the University of California at Berkeley, stationed at the UC Cooperative Extension office in San Luis Obispo. He has also seen and recently received numerous reports about oaks appearing in bad shape.
“This is a very severe drought, by some accounts the most severe on the Central Coast in 500 years, but our native oaks have been around for a long time and have been through this before,” he said. “A few may succumb, especially those on poor sites — shallow soil, south-facing slopes, weakened by disease or age — but our beautiful oaks will survive.”
Evidence from the medieval mega-droughts that occurred over a millennium ago indicates that local oaks are resistant to drought. Dr. Terry Jones, an anthropologist at Cal Poly, has done research on the effects of the Medieval Dry Anomaly on Native American populations.
In using Native American bone remains, anthropologists have found that dental cavities increased significantly during that time. Dr. Jones (and other anthropologists) attributes the increase in cavities to the relative persistence of acorns, which are rich in carbohydrates.
In other words, Terry feels that more tooth cavities are circumstantial evidence that oaks survived and continued to produce acorns during the drought.
Dr. Tietje went on to say, “It is important to be aware that although an oak may appear dead due to early leaf loss (most notably, the blue oak is drought deciduous) or perhaps due to complete defoliation by the oak worm, more likely the tree is alive and well and will refoliate next spring. The best advice: Wait and see. The best prescription: Pray for rain!”
At this point, oceanographic and atmospheric conditions are pointing to near normal amounts of rainfall this rain season.
PG&E Safety Tip: Never, ever touch a downed power line or go near one. Power lines are not insulated like power cords. Always assume the power line is live. Call 911 immediately to report a fallen power line.