We know the Dakotas experience some of the most unpredictable weather in the country (see http://www.mwb-s.com/blog/2014/12/8/dealing-with-the-unpredictable), and this spring has not disappointed us with those surprises. South Dakota had the driest start to 2015 through April based on historical standards, with less than 2 inches of moisture over that period (https://www.ncdc.noaa.gov/sotc/service/national/Statewideprank/201501-201504.gif). And, in Rapid City, we had a high of 84 degrees on March 14. I should probably also mention it snowed two days after that.
Now it appears someone has flipped the switch on us, because our highs can’t climb out of the 50s and 60s in mid-May. On Mother’s Day, May 11, we had over 13 inches of snow. Our month-to-date rainfall is now 6 inches, well ahead of the 3.86 inches we average in May. Climatologist are now indicating this has to do with the onset of El Niño, which is the cyclical warming of the Pacific Ocean that tends to impact the climate on every corner of the Earth.
Formally called the El Niño Southern Oscillation (ENSO), it typically leads to warmer and drier winters and wetter and cooler summers for the upper Midwest. Starting to feel familiar? While these effects are not always certain, they are statistically much more likely during an El Niño.
It is believed the effects of ENSO’s cool-wet summers causes lower corn yields, lower winter wheat yields, and reduces tilling (http://growingsouthdakota.com/features/2015/04/el-nino-will-impact-field/).
Andrew Freedman, science editor at Mashable.com, noted on PRI’s The World that extreme weather is expected with El Niño events, and it is hard to chalk it up entirely to climate change (see the May 26th interview at http://www.pri.org/programs/the-world).
Freedman eloquently explains the media may be quick to link stories of extreme weather events to climate change because it may make for an entertaining news story, but climate has always been variable, both in the short-term and the long-term. He points out that climate change certainly plays a role in some of these events, however, we can’t directly measure how much an extreme event can be attributed to climate change, because these events are typical with El Niño.
What is most important to understand with El Niño it provides a basis for forecasting, so people like ag producers should be well aware of how it will affect them. If producers aren’t heeding the forecast, by now they should start considering it.
And we should remember, each coin has two sides. El Niño isn’t bad news for everyone. While the tragic flooding in Texas is likely a consequence of El Niño, the silver lining is this is quenching a region that had been in a severe drought. In the Dakotas, we can always appreciate a warmer winter, although it will likely be tough on the skiing industry in the Black Hills.
Another point to remember is all climatologist say that no two El Niño are the same. So while there may be some general patterns that emerge each time ENSO fires up, it doesn’t mean it will be exactly like the last time we may have experienced this.