Yesterday, the flow prediction for the Middle Fork of the American was made for 2017: It was great! 7 days a week of excellent rafting flows with the potential for this to be 24×7. Wow! The South Fork prediction will be updated in February and finalized in May. It is virtually guaranteed to be similar.
Let’s go boating in 2017. It is going to be a great year!
When the National Oceanographic and Atmospheric Administration (NOAA) made its forecast for the winter of 2016-17 the watershed of the American River had equal chances of wet or dry conditions. As of January 19, 2017, however, near record rain and snow have clearly tilted things toward “wet” and recently resulted in flows on the South Fork that peaked at 33,000 cfs (22 times normal midsummer flows). Snowdrifts in the drainage of the American River are 20 feet deep in places with snowpack at 175- 200% of normal for this time of year.
On dam-controlled rivers such as the South and Middle Forks of the American such wet conditions will often result in excellent rafting flows not only for one year, but rather for two. We look forward to enjoying this water in both the 2017 and 2018 seasons! So how did this happy situation occur? Is El Nino responsible? Is the drought over? What happened to climate change? Let’s visit NOAA’s website to search for answers to these questions…….
American River Questions and Answers:
Q: What about El Nino?
A: “El Nino” is actually half of the ENSO, which stands for the “El Nino/La Nina Southern Oscillation”. This is a periodic fluctuation in ocean surface temperatures in “area 3.4” of the Pacific Ocean east of Hawaii which profoundly influence weather patterns worldwide. El Nino represents a warmer than average ocean surface temperature condition, La Nina represents the opposite-cooler. Last winter these temperatures were so high that they set all time records and since El Nino usually brings wet conditions to the Southern Hemisphere no one was surprised when Chile and the American Southwest were pounded by extreme storms. Where things became less predictable was farther north. NOAA’s 2016 forecast was for a 71% probability of 120-140% above normal precipitation in the watershed of the American River. This was despite the fact that El Nino years are on average either neutral or drier than normal in this region. Actually the precipitation was roughly average on the American in 2016, but given the extended drought in California, everyone celebrated! But was this change due to El Nino?
Q. So what are we having this year, El Nino or La Nina, and what effect does it have on our weather?
A. As 2016 ended, ocean temperatures dropped enough to declare a La Nina and this is ongoing. It is so weak, however, that it was thought that the La Nina influence would be insignificant. Prudently, NOAA’s forecast for the winter of 2016-17 was essentially for a “normal” winter for the American River region with little or no predictable effect by the ENSO expected.
Q: So what caused all the rain and snow in January and why wasn’t it predicted?
A: First of all, let us address the common misconception that El Nino always means wet and La Nina always means dry. Globally speaking this is incorrect because it depends on where you are. While La Nina conditions have correlated with dry and warm weather in the Southern Hemisphere and even in Southern California, in the watershed of the American River the wettest recorded winters such as 1982-83 have generally been La Nina conditions or neutral/normal ENSO events.
Secondly, before we abandon the ENSO completely as a strong influence this season, consider that as the 2016-17 winter began the ENSO oscillation in ocean temperatures was incomplete. The cooling in Area 3.4 continues as I write this and a strong La Nina could still be happening.
In addition, the current La Nina may actually be more significant than we think. The reason is that the overall baseline for ocean temperature has shifted. We now know that 2016 was the warmest year on record worldwide and this was reflected in an increase in baseline ocean temperature. Therefore, to achieve a significant cooling the rise in baseline needs to be accounted for; otherwise the measured La Nina may be an underestimate of the climate “forcing” or influence involved.
Finally, there is evidence that a new factor needs to the considered. The circulation of cold air around the Arctic region known as the Polar Vortex is being influenced by climate change and the resulting melting of the Arctic sea icepack. The Vortex is developing a “wavy” pattern that increases the probability that Arctic cold air will collide with the stream of moist tropical air flowing across the Pacific Ocean known as the “atmospheric river”. This river is huge, often over 200 miles wide and carrying as much water as the Mississippi River! The storms it creates often exceed those that batter the infamous “Hurricane Alley”. This river delivers 80% of California’s precipitation in 3 to 4 large storms annually when the “storm window” opens. This is the process that is presently bringing snow and rain to the American River watershed and its boom and bust pattern is “normal”. However, the Polar Vortex could affect these patterns by alternating snow with rain and augmenting flooding as a result.
Q. So did NOAA miss on its forecast for 2017? What would this mean for the future?
A. Before we criticize NOAA for not predicting the wet season of 2017, we should remember that meteorologist’s always deal in probabilities, never certainty. Forecasting the weather (short term) is always harder to predict than trends in the climate (long term). When NOAA forecast a 71% probability of above normal precipitation last season (2016) on the American River, this also implied a 39% probability of dry. The “gambler’s fallacy” is the very human process of focusing on the desired or most probable result, while failing to appreciate that the opposite result is also highly probable.
So what do we know for sure? Clearly we need more, not less, climate science and NOAA is an essential part of that effort. We also know that carbon dioxide levels increased in 2016 even more than the IPCC warned or expected. We also know that the isotopic “fingerprint” of the carbon dioxide that produced this increase is predominantly coming from burning fossil fuels. We also know 2016 was the hottest year on record worldwide and the oceans are absorbing most of this heat.
In conclusion, it is critical that we as a species be very careful about altering systems we poorly understand and which have profound effects on ourselves and the other organisms of the planet. Climate scientist Dr. James Hansen of NASA has applied the term “climate chaos” to the emerging pattern of extreme weather, violent storms, prolonged drought and warming of the seas. Denial of human induced climate change is simply ignorance. We cannot afford it.
Join us as we enjoy the great water for rafting this coming rafting season. We are grateful for it and count our blessings. We will also struggle to conserve the ecosystems that make our lives possible and continue our longstanding effort to save rivers.
Greetings from the River,
Scott, Penny, Scotty, Brian, Heather and the MaLode Crew
P.S. Charlie the RiverDog also looks forward to seeing you soon!