Article Keith Abeles, Program Manager, Sonoma RCD
What’s all the hype about El Nino? As of late September, surface waters in portions of the eastern tropical region of the Pacific Ocean were over 4 degrees Fahrenheit higher than normal, making for some of the strongest El Nino conditions on record. Because we have seen big rains come during El Nino events, many are speculating an epic rain year is on its way. But is it? No one really knows. El Nino is a poorly understood, variable weather phenomenon. In the 65 years it has been studied, only two El Ninos considered to be very strong resulted in major rains in northern California. Those years were the winters of 82-83 and 97-98. There have also been years with significant El Nino conditions resulting in average and below average rains.
What is El Nino?
It is the weather occurrence where surface waters in the equatorial regions of the Pacific Ocean cool on the western side and warm on the eastern side. This occurrence moves the jet streams, the high altitude currents that drive storms around the world. It is a natural occurrence, happening regardless of climate change. It does not create more water, but shifts where rain and storms fall. Often it pushes the action to California.
So will it bring much needed rain to northern California? The National Oceanic and Atmospheric Administration (NOAA) Drought Task Force says it is possible, but it depends. If the El Nino holds strong into January through April of 2016, the task force anticipates a wet winter. If the El Nino breaks up at the end of 2015, then other variables will determine if it is a wet or dry winter. The task force and other climatologists also tell us that southern California is more likely to have above average rain than northern California.
Other weather patterns will need to play out along with the El Nino to bring heavy rains. The Pacific Decadal Oscillation, Madden-Julian Oscillation, Arctic Oscillation, and North Atlantic Oscillation are other existing phenomenon that have impacts on our weather and can affect the outcome of this winter. For the past few winters, extremely high pressure ridges have set up off the coast of California, driving the storms north of us. If this ridge sets up again it is not clear if El Nino will punch through it, or how they will interact.
El Nino generally pushes the jet stream south, which can mean wetter years in southern California than in northern California. It tends to set up a north-south gradient for dry and wet that lands in variable places in the state. We could end up on the northern, drier side of that gradient. The NOAA Drought Task Force tells us that “models show a 50% probability that precipitation would be at least 140% of normal, and dry conditions are unlikely”. Promising, but 50% does not sound like a lock on a wet winter. Even if we got 140% of normal rains, that would not make up for 4 years of drought deficits. We would still have a long way to catch up, and even more so in other parts of the state.
So what to do?
Producers should do the same things that serve them best before every winter.
Prepare for rain. Clean your gutters, clear your ditches and drains, put things away that need to be protected, clean up your outdoor work areas, cover things up that need it, and make sure areas that are difficult to access or deal with in winter get the attention they need. Don’t wait till the last minute, do it now. It is essential to conclude soil disturbing activities, and cover bare soil with mulch, or reestablish cover crops and vegetation before big rains hit.
Make sure water can flow where it needs to, while maintaining plant cover wherever possible to prevent erosion. Know and follow any applicable rules when clearing ditches and areas where water flows. Be aware of the requirements of the recently established Sonoma County Riparian Ordinance.
Use rains to your advantage. Consider developing water catchment in tanks and ponds to save water for drier parts of the year. Contact your local RCD to get technical assistance. Refer to the numerous resources found at the end of our newly revised Slow It, Spread It, Sink It, Store It! guide at: www.sonomarcd.org/htm/rainwater.htm. Increase infiltration of water where possible with berms, contouring, swales and other means to recharge ground water, protect water quality, and minimize downstream impacts. The more water we can keep on site and out of creeks during high flow events, the better.
Conserve water now. With no guarantee that it will rain a lot this winter, assume the drought will continue. Use water as efficiently as possible, and only what you need. It is in our best interest to develop techniques, projects and habits that serve us into the indefinite future. Annual and multiyear droughts are part of our natural cycle. Climate experts predict more variable weather in the future, including longer and more intense droughts. Let’s use the current drought to help us develop pragmatic ways to manage our water and be prepared for droughts like the one we are still in. Agriculturists have a constant need to innovate to survive, and this is certainly no exception. While we all hope for rain, let’s continue to prepare for more drought. For more info log onto NOAA’s web site at: www.elnino.noaa.gov.