Christmas has come early in California as the state has just been hit with one of its biggest rainstorms in recent memory. As of Wednesday morning, San Francisco had received more rain, 3.76 inches, since Sunday than it did all of last year, 3.38 inches. Santa Barbara broke its record for December 2nd rain on Tuesday with 2.14 inches. Los Angeles was also deluged, as many residents prepared for flash floods and other rain-related delays. Mudslides were anticipated in areas that have recently been hit by wildfires. The coastal community of Camarillo placed 75 homes under mandatory evacuation over fear of landslides, which are especially susceptible after periods of extended drought.
And it has been dry in California. The state is in its fourth consecutive year of drought, and the impacts are starting to be felt at a human level. Small, inland communities have run out of water and are using portable showers in some cases. Strict watering restrictions have been issued across the state and enforcement efforts are ramping up. San Diego has big plans to turn sewage water into drinking water. While this rainstorm is extremely welcome relief at a human level, in the long-term the specter of drought and climate change in California persists.
Meteorologist Jan Null told the Washington Post that “the 3-season deficit for San Francisco at the beginning of the rainfall season was 26.07 inches.” He went on to explain that to reach normal would take 49.73 inches of rain. According to Null, every inch of rain that San Francisco gets only alleviates about three percent of the long-term water deficit.
This type of heavy downpour event can also disrupt water and agricultural systems. The National Climate Assessment earlier this year found that these isolated deluges can cause flash floods that overrun storm infrastructure and contaminate drinking water sources with agricultural runoff including fertilizers and chemicals. These precipitation bursts can also damage the crops themselves by flooding fields of corn, soybeans or other crops for long periods of time.
Furthermore, extreme storms like this don’t necessarily recharge the groundwater reserves as well as more moderate rain events. The drought in California is taking a major toll on the state’s groundwater sources, which farmers rely on to saturate the state’s massive agricultural industry. According to the University of Kansas Geology department “the amount of groundwater recharge from a gentle rain of long duration generally is greater than the recharge from a heavy downpour of short duration, providing all other factors are equal.”
Climate Central reports that the West Coast rain this week is being produced by an “atmospheric river” coming from the tropics and that “near record-warm ocean waters” off the coast will also provide more “liquid fuel.”
National Weather Service meteorologist Gary Sanger told Climate Central that the rain “won’t ease the drought” because the state is so far behind.
A recent National Science Foundation study also found that the record drought in California is directly tied to climate change. Scientists have determined that climate change makes heat waves stronger and more frequent, which exacerbates drought. This effect is amplified by the reduction in precipitation that is already happening due to climate change in the southwestern United States.
Where the rain turns to snow in the mountains is where it could be most impactful. Snowpack across the Sierra range is only about 20 percent and the state depends on this resource in the spring to provide drinking water for millions of people. Snowfall totals from this week’s storms are expected to be around two to three feet high in the mountains.
Earlier this year signs indicated that a strong El Niño could form over the course of the year — which was predicted to bring record hot global temperatures and increased precipitation in California. The record-high global temperatures are here, as 2014 is predicted to be the hottest year on record, but California had not broken through the rain barrier until now.
The precipitation pattern in California right now resembles what is known as the “pineapple express,” as pointed out by Paul Huttner, chief meteorologist for Minnesota Public Radio. Pineapple express weather patterns are associated with El Niño years, as they bring moist air from Hawaii to California. This week’s storms are being generated by more equatorial tropical weather, but the similarity is still there.
On Tuesday, the Australian Bureau of Meteorology put out a press release saying that “many climate indicators remain close to El Niño thresholds, with climate model outlooks suggesting further intensification of conditions remains likely:”
Regardless of whether an El Niño is declared, El Niño-like effects are likely, as shown by the Bureau’s December–February Climate Outlook, which shows a drier and warmer summer is likely for many parts of Australia.
So while El Niño means welcome rain for California, across the Pacific it means more devastating drought and heat for Australia, which is locked in a prolonged drought similar to California’s.