While it seems as if the entire rest of the nation was huddled in a deep polar vortex, northern Californians have been enjoying blue skies, temperate heat and even sunbathing on the banks of Lake Tahoe. In January.
It’s no secret that California has an arid, Mediterranean climate, but this year’s unseasonably dry weather still has many residents shivering in fear of the D-word: drought.
“It’s scary,” says Clayton Pioneer weather columnist Woody Whitlatch, a former longtime PG&E meteorologist who has crunched rainfall data of the past 165 years.
It is scary when you see that the 2013 calendar year was the driest on record, with only 5.59 inches of rain measured in San Francisco. The average is about 22.5 inches. The “water year,” which experts use, runs July 1 through June 30, and so far totals for this water year are shallow: just 2.08 inches of precipitation since July.
The thought of a drought brings fears of severe water rationing, empty swimming pools, brown yards and reduced toilet flushing, all things that live in the memory of many local residents who experienced the severe drought of 1976-77.
Are we in a drought?
One of those people is Contra Costa Water District spokesperson Jennifer Allen, who remembers the drought back then as a child growing up in the North Bay. “We put a brick in our toilets,” she says. “Now, thanks to low-flow toilets, that’s a thing of the past.”
Still, she says it is impossible to call our dry weather pattern a drought because “all the information isn’t in yet,” she says. “We don’t know what the weather will bring this winter, or what the state water allocations will be.”
Basically, a drought is determined by the amount of water available, she says, and good planning and conservation methods, as well as increased supplies from Delta waters, have kept the water supplies in a fairly good position to serve customers.
“But we rely on the Sierra snowpack, so all that can change if we continue to see dry weather patterns.”
She says that the water district has an internal team of experts working on a scenario if that happens, and will have a plan in place if rationing happens later this summer, she said.
It’s not clear how much rain, or more importantly, how much Sierra snowfall, is needed to avoid water rationing. “Weather is an art, not a science,” she says.
Dry period or climate change?
Whitlatch agrees that the unpredictable nature of weather makes it nearly impossible to foresee what is beyond the horizon, despite the advanced meteorological technologies available today.
“Currently, California is sitting below a stubborn high-pressure ridge that isn’t letting go,” he says. “It’s bumping all the wet weather systems north and east of us. That in part is what’s causing the severe weather in other parts of the country. That weather has to go somewhere.”
Californians are used to that high pressure ridge, as it has been a frequent companion for the past three years.
Using the data he’s compiled (see graph), Whitlatch says that we are in a three-to-four year dry weather pattern.
Based on “water year” data, the last two years have been pretty dry, with 2012-13 ranking 42nd of 165 years, in the 25th percentile of rainfall, and 2011-12 ranking 35th, in the 21st percentile. “If we hadn’t had such a wet December in 2012, the 2012-13 water year would have ranked much drier,” he says.
Still, Whitlatch says that he sees the current pattern as just that, an event, and not a sign of climate change. However, he says that doesn’t mean that climate change does not exist.
“It’s a good chance we are in climate change, and maybe 30 years from now we can look over the patterns, and really determine that yes, we are getting drier,” he says. “But it’s just too early determine that with the rainfall records we have now.”
Still, in the second decade of the 21st Century, it’s hard to understand why we can’t have more of a positive impact on the weather via technology.
“There is always cloud seeding,” Whitlatch says, referring to the process of adding moisture to existing rainmakers. “But you need clouds for that, and we just haven’t had much cloud cover at all. You can’t make water where there isn’t any.”
He agrees with Allen that residents are more savvy now in dealing with water shortages than we were in the past. “Back in 1976-77, we didn’t have a clue how to handle a drought. Now, water companies, and water users, are more prepared.”
How to be prepared for water shortages and rationing is on the minds of many people, according to Nicole Hackett, the Pioneer’s gardening expert. “I hear it all the time now: ‘What should I be doing if there is a drought?’ People are scared,” she says.
Hackett’s column this issue (see page XX) details some ideas, but she is quick to point out that people need to examine their water usage, and make sure they are “water wise.”
“Are you watering your lawn, or the sidewalk? What time of day do you water? There are very simple things homeowners and garden aficionados can do to make sure they are getting the best bang for their water buck, so to speak.”
She and Allen suggest contacting the CCWD to see about some of the free programs offered to customers that will help residents gauge their water usage.
“There are tools available, such as programs to help replace landscapes so that they are more ‘water-wise,’” says Hackett. “I’ve seen some lovely dryscapes in the Clayton Valley area that have little or no grass. Not only does it save on water, but it is a lot easier to tend.”
Still, looking ahead, Whitlatch says that by reviewing historical data, he suspects that the rest of the 2013-14 water year will be about 75 percent of average.
He came to that conclusion after sorting through June-December rainfall in San Francisco in the past 165 years, coming up with an average for 25 of those years. That average is 13.04 inches.
While he did not study the jet stream charts for those 25 years, Whitlatch says that he did note that a persistent high pressure ridge over the West Coast, like the one we are currently experiencing, was mainly responsible for the abnormally dry fall and early winter seasons. So, during at least 20 of the 25 dry first six-month segments of the water year, those with at least 75 percent of normal January to June rainfall had some breakdown of the ridge during the second six-month portion of the water year.
In other words, statistically speaking, we’re likely to see some breakdown of that stubborn ridge.
And looking ahead at one weather model, Whitlatch says there is a chance of “some decent rain” beginning after Jan. 20.
“Weather” or not that happens, he, like all residents, is hoping for the best, and preparing for a drought.