There hasn’t been a significant storm in some parts of Panama since early May. The fertile highlands of Ethiopia are experiencing one of the driest summers in forty years. Since the start of modern rain records in 1901, India had its fifth driest June. These are early signs of something much bigger developing in the Pacific Ocean, and the full impact hasn’t yet materialized. They are not isolated weather anomalies dispersed throughout the world.
A Super El Niño is emerging. When ocean surface temperatures in the central and eastern tropical Pacific are more than two degrees Celsius above average, climate scientists use that term. According to Environment Canada meteorologist Bill Merryfield, the current build-up is predicted to peak at a temperature above 3 degrees Celsius, which would be “literally off the charts.” Speaking with professionals who observe these patterns gives the impression that even they are a little uneasy about what the models are displaying.
According to the National Oceanic and Atmospheric Administration, there is a nearly 70% chance that this will be the strongest El Niño ever recorded. For background, NOAA’s records date back to 1950. The violent 1982–83 event held the previous record. The downstream effects are genuinely hard to predict with confidence because what’s coming might surpass it and it’s arriving against a background ocean that’s already warmer than it has ever been.
Precipitation will be the most obvious effect for the United States. The southern storm track, which is essentially a conveyor belt of weather systems that feeds moisture into the West Coast, the Southwest, the Southern Plains, and the Southeast, is often energized by strong El Niño events. All of those areas are expected to see above-average precipitation, according to OpenSnow forecasters. Above-normal snowfall is being reported in Arizona, California, Colorado, Idaho, New Mexico, Oregon, Utah, and Wyoming. Warmer El Niño winters and more snow may seem counterintuitive, but in mountain states, warmer temperatures simply result in more atmospheric moisture, which still freezes at elevation.
Since nothing about the current baseline is typical, it is still unclear how much wetter this winter will feel in comparison to a typical strong El Niño year. Ocean temperatures in the tropics have already increased due to long-term warming, which may intensify the heat signature that El Niño is attempting to imprint on global weather. Daniel Swain, a climate scientist at UC Santa Barbara, called the current trajectory “genuinely remarkable,” pointing out that the event is already at record-tying levels and is still getting worse as fall approaches.
Increased precipitation is also predicted for the East Coast, the South, and the mid-Atlantic. When southern storm systems stall or stack up, the risk of flooding increases along these corridors. Strong El Niño winters, the most often mentioned of which was 1997–1998, provide historical precedent for what a wet season can do to drainage systems and agricultural land that isn’t built for sustained inundation.
The unevenness makes communication more difficult. The United States’ northern tier, which includes the Great Lakes region, the northern Rockies, and a large portion of the Upper Midwest, is expected to experience warmer, drier weather with less snowpack than usual. In some of the same western states that will have experienced significant winter precipitation, less snowpack results in less spring runoff, which puts strain on reservoirs as summer approaches. Benefits from weather systems are not always distributed equally, and this one is no exception.
There’s a strange tension between the scope of what’s being predicted and how subtly it’s being absorbed as all of this takes place. In the equatorial Pacific, the ocean continues to warm while people plan their vacations, farmers plant cover crops, and city planners prepare for the upcoming budget cycles. The models continue to rise. Furthermore, the winter they are forecasting is unlike anything we have ever experienced in a number of ways.
