From the Grand Junction Free Press (Hannah Holm):
As chill and darkness creep into September mornings and parent-teacher conferences approach, it’s natural to start wondering about what kind of winter we can expect. And, in turn, what kind of water conditions will follow for farmers, rafters and fish.
There’s been a lot of talk lately about the “Godzilla” El Niño headed our way. El Niño, Spanish for “the baby,” refers to a warming of the eastern tropical Pacific Ocean, which can result in dramatic weather around the globe. According to the LA Times, Bill Patzert of NASA’s Jet Propulsion Lab coined the term “Godzilla El Niño” in referring to the fact that we appear to be on track to experience one of the strongest El Niños on record.
So what could this giant reptile-baby do for the Colorado River Basin, where a 15-year drought has helped push water storage levels in Lakes Mead and Powell to record lows?
According to the California Weather Blog, a strong El Niño shifts the odds strongly in favor of a wet winter for all of California. This could help the state begin to recover from its record-setting drought. Unfortunately, above average temperatures are also forecast from the west coast to Utah, which could mean higher snow levels and more rain, with the attendant increased risk of floods, mudslides and general mayhem.
A wet California won’t do much for supplies in the Colorado River, but could ease demands a bit. Southern California relies extensively on Colorado River water to supplement what it gets from its own mountains — which has recently been next to nothing. So more precipitation falling within California should help get the supply portfolio for the Los Angeles metro area a little more back in balance.
It’s not nearly as clear what El Niño will mean for the Colorado River’s headwaters and Colorado ski areas. The Weather 5280 blog did an extensive review of how past El Niño events have affected precipitation patterns around Colorado, and found a mixed bag. For the state as a whole, past El Niños have coincided with increased average precipitation in the summer, fall and spring, but average winters. Breaking it down by region, Western Colorado has gotten the biggest boost to precipitation in the fall, but actually had drier winters in El Niño years.
The Denver Post reports that, while there’s not a strong correlation between El Niño events and average precipitation in Colorado, many of the state’s biggest storms have occurred during El Niño years.
The National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center (CPC) three month outlook, which takes El Niño into account along with other factors, shows that the entire Southwest is likely to be wetter through the fall, with the strongest tendency squarely focused on Arizona and a diminishing but still positive tendency for southern California, southern and eastern Nevada, all of Utah, Colorado and New Mexico, and most of Wyoming.
The temperature outlook over the same period shows equal chances of warmer and cooler temperatures for most of the four-corners states, with increasingly warmer-than-average conditions as you look to the north and west. You can find this information and related reports on Western Water Assessment’s climate dashboard at http://wwa.colorado.edu/climate/dashboard.html.
So — what kind of winter are we in for? It’s not exactly clear, but our wet spring and summer have already reduced the probability of a formally declared shortage in the lower Colorado River Basin within the next couple of years, which would initially result in reduced Colorado River deliveries to some Arizona farmers. With some help from El Niño, it looks like drought conditions in most of the Colorado River Basin on are their way out, and California should get at least some relief.
In terms of the ski season, take full advantage of any nice, big fall dumps, because there’s no guarantee that more big storms will follow.
This is part of a series of articles coordinated by the Water Center at Colorado Mesa University in cooperation with the Colorado and Gunnison Basin Roundtables to raise awareness about water needs, uses and policies in our region. To learn more, go to http://www.coloradomesa.edu/WaterCenter. You can also find the Water Center on Facebook at https://www.facebook.com/WaterCenter.CMU or on Twitter at https://twitter.com/WaterCenterCMU.