While 2013 was one of the driest years on record for the Bay Area, that alone wasn't enough to create a drought as extreme as the one California is seeing now.
“As soon as January last year came around, the rainfall essentially just turned off,” NWS Hydrologist Dr. Mark Strudley said.
This is how we got here:
“Not only have we had a shortage of rainfall over the duration of the rain year, but we’ve had essentially very little rainfall through the latter half of last winter,” Dr. Strudley said.
An unfortunate turn in the weather parched the Golden State in a record-breaking series of dry months.
What made this year worse was a weather pattern that mirrored the drought years of the 70s.
“We had a large ridge of high pressure over the West Coast, and that ridge of high pressure kind of prevented storm systems from making their way into the Bay Area,” NWS Meteorologist Logan Johnson said. “In those drought years California in the late 70s, it’s also important to point out those were also some of the coldest and snowiest on record for the East Coast. So you could see nearly the exact same pattern back in the late 70s that we had this year.”
Dr. Strudley says California has seen “above average conditions this water year, but the last two and half have been basically way below average, and in a lot of places the total rainfall essentially has crept lower and lower and lower.”
The impact on the Bay Area heading into the typically driest time of year will depend on your primary and secondary sources for water.
“It doesn’t depend so much on where you are in the Bay Area as it does if you’re getting supplemental supplies from state water project or Central Valley Project sources,” Dr. Strudley said. “Those areas are a little more resilient to the effects of the drought and the shortage than places fed strictly by local water sources, whether they’re surface or groundwater.”
The quality of that groundwater may begin to suffer as levels drop below ground.
“Whether its salts, nitrates or other things, it’s a concern for agricultural users and it’s a concern for drinking water,” Dr. Strudley said.
- Special Coverage: Bay Area Drought Watch
So what happens then if our drought were to extend into another year? Based on water reserves and anticipated demand for the coming year, the results for California could be quite dire.
By the numbers, with this year’s runoff, we will have close to 18 million acre-feet of water available, of which an average of 11 million will be consumed from summer into the fall. This sets up California heading into the next rainy season with 7 million acre-feet available, a supply starting off that could be less than next year’s anticipated demand.
Dr. Strudey says, once those long-term supplies are gone, “That’s when we really have nothing else to rely on except what the weather is going to bring us.”