Hoping for a March Miracle to bail out California’s dry winter? It’s not likely.
A review of more than 100 years of rainfall records of major cities in California — including San Jose, Los Angeles, San Diego, Santa Rosa, Redding and Fresno — shows that none have ever finished the rainy season with normal rainfall totals after ending January with the amount of rain they’ve had so far this winter.
In San Francisco, where rainfall records date back to 1849, the odds are only a little better. Just twice has the city’s rainfall total recovered to its normal level of 23.65 inches by June 30 after being where it is now, at 8.53 inches, from July 1 through Jan. 31.
In Eureka, it’s happened three times since 1885. In the rest of the cities, not once, even though their weather records also date back to the late 1800s.
In other words, California winters are like Olympic ski racers. Stumble at the beginning of the race, and its very difficult to catch up by the end.
“The odds are against you with a bad start,” said Jan Null, a meteorologist with Golden Gate Weather Services in Saratoga, who compiled the data. “Usually there just aren’t enough opportunities to recover.”
California’s Mediterranean climate means that most rain every year falls during four months: December, January, February and March.
In San Francisco, 71 percent of the annual total, on average, occurs in those four months. In San Jose it’s 70 percent. In Sacramento, it’s 68 percent and in Los Angeles, it’s 78 percent.
So far this winter, December was dry, January was about average in most areas — saved by one big storm on Jan. 8 and 9 — and February so far has been bone dry and hot, with forecasts calling for another 10 days of warm, sunny weather.
While it could still rain considerably between now and April 1, much of the state remains in a sizable rainfall deficit this winter.
“There’s a reason they call it a Miracle March,” said Bill Patzert, who worked for 35 years as a research scientist and oceanographer at NASA’s Jet Propulsion Laboratory in Pasadena. “That’s because it doesn’t happen that often.
“Miracles are hard to find,” he added. “There are plenty of them in the Old Testament, but there aren’t that many in California when it comes to water. I wouldn’t be betting what’s left of your 401K on any miracles.”
The rainfall totals from last July 1 through Jan. 31 are not dismal. They just aren’t big enough, history shows, to get to a ”normal year,” by June 30, which Null defines in his research as the average rainfall between 1981 and 2010 in each area.
In San Francisco, for example, this is the 49th driest winter rain season through January back to 1849. Only two seasons this dry or drier have ended the full season with at least normal rainfall.
For San Jose, where records go back to 1892, there were 4.81 inches of rain from July 1 to Jan. 31, or 55 percent of normal. That makes this winter the 32nd driest season through January. But no seasons in San Jose that have been this dry or drier have ended with at least normal rainfall.
Los Angeles is worse off. LA has received only 1.96 inches, or 25 percent of normal, for this time of year, making this winter the 11th driest season through January. No seasons that have been this dry or drier in LA at this point in the winter have ended with at least normal rainfall.
After suffering through the worst drought in the state’s recorded history from December 2011 to March 2017, California residents, water managers, farmers, fire chiefs, fisheries biologists and ski resort owners are jittery. The big fear: What if last winter’s soaking storms — the deluges that drove Gov. Jerry Brown to announce an end to the drought emergency last April — were just a one-year fluke and the state is heading back into another drought?
“We had one really good atmospheric river last month,” said Mike Anderson, California’s state climatologist with the Department of Water Resources. “I got almost three inches of rain at my house in Davis. That was pretty exciting. But ever since then in the north we’ve only had a few little storms without much water vapor, and the south really hasn’t had anything.
“The possibility of getting back to average this winter is pretty slim,” he said. “We need to make conservation a way of life and be prepared for dry years when they show up.”
Meanwhile, the Sierra Nevada snowpack, the source of one-third of the California’s water, is at just 24 percent of the historic average. Lack of storms, and hot temperatures have put it at levels last seen during the drought.
The good news is that last year’s storms filled many of California’s largest reservoirs. Hydrologically, that’s money in the bank. Combined, 46 of the biggest reservoirs in California are at 106 percent of their historic average storage level for the first week in February, according to state records.
The largest, Shasta Lake, near Redding, was 74 percent full on Monday, or 108 percent of the historic average for that date. Similarly, San Luis Reservoir, between Gilroy and Los Banos, was 85 percent full, or 106 percent of average.
The largest reservoir in Santa Cruz’s water system, Loch Lomond, is 93 percent full. And although the 10 reservoirs operated by Santa Clara Valley Water District are just 26 percent full, in part because of state storage limits due to needed earthquake upgrades, the district’s groundwater supplies, which make up half the total water supply in Santa Clara County, recovered entirely last year from the drought.
The seven reservoirs operated by East Bay Municipal Water District are 81 percent full.
“Our water supply isn’t as worrisome right now, but the snow pack is very low, and we certainly want to see that change,” said Andrea Pook, a spokeswoman for the district, which provides water to 1.4 million people in Alameda and Contra Costa counties. “We want people to remember to use water wisely, and keep that mindset.”
