The 2016 water year ended on Sept. 30, which puts last winter to rest. Although snowfall totals were mostly in the average category in 2015-16, the region got a healthy dose of precipitation (rain combined with the water equivalent of snow). And, for an area in the midst of severe drought, water is what the regional environment needs most. Of course, locals and visitors prefer that our winter moisture comes in the form of snow, especially if most of it piles up on the ski slopes.
But did last winter’s Godzilla El Niño match up to the media hype that Californians were inundated with? Headlines began popping up in early summer 2015. “El Niño is coming!” “Southern California better batten down the hatches!” It was enough to make one run to the Tahoe Sierra where many hoped for a blockbuster winter. After four dry years, Truckee-Tahoe residents were looking forward to an epic season with lots of rain and snow.
As intense El Niño conditions developed in the Pacific Ocean throughout the summer and autumn seasons of 2015, most forecasters became confident that much of California was likely to be wetter than normal, especially the southern portions of the Golden State. By many metrics the El Niño Southern Oscillation (ENSO) event of 2015-16 was the strongest ever recorded, but it certainly confounded predictions. Instead of a wet south and dry north the inverse occurred and Northern California and the Pacific Northwest were hit with the bulk of rain and snow. Southern California was supposed to be hammered with rainfall last year, but it came in dry instead with only 55 percent of average.
“2017 looks to be an average winter, which in the Tahoe Sierra
is pretty darn good. In most years a big chunk of our snow
and rain comes from the moisture received from a half
dozen big storms. As long as they show up, we’ll be fine”
On cue with expectations, last winter started off wet and early snowfall enabled many Truckee-Tahoe resorts to open terrain for the Thanksgiving holiday period. By New Year’s Eve, the Tahoe snowpack ranged from 5 to 8 feet deep with 136 percent of average water content. At Squaw Valley, it was only the fifth time in the resort’s 60-year history that it was able to open all of its terrain by Christmas Day.
Storms and cold temperatures in January maintained the above-average snowpack along with excellent skiing and riding conditions at Tahoe resorts. But the month of February was a bust with little additional rain or snow during one of the normally wettest months. The lack of mid-winter precipitation, while not uncommon, was another indicator that El Niño impacts are unpredictable. A robust storm pattern in March turned things around, however, and the snowpack again surged in the higher elevations.
Last winter, Squaw Valley picked up a total of 21 feet of snow at its base with 41 feet on the upper mountain. That stark contrast between elevation-based snowfall totals has been more pronounced in recent winters as temperatures have often ranged warmer during storm episodes. These modest numbers in no way denoted epic snowfall last year, but skiing and riding conditions were the best since 2011.
The Central Sierra Snow Laboratory is located near Donner Pass. The lab’s snowfall tally of 31 feet in 2016 was about 10 percent below its annual average of nearly 35 feet. That ranks last winter as the 64th snowiest since 1879. Precipitation, however, was much more generous. Nearly 68 inches of precipitation was measured, putting 2016 in a tie with 1872 as the 32nd wettest at Donner Pass since 1871. There is little doubt that the 2016 ENSO event influenced our weather as the season was warmer and wetter than normal, a classic pattern associated with a strong El Niño. But the topsy-turvy aspect of where the precipitation fell shows the unpredictability of weather in the West even with a strong ENSO signature. Ultimately these atmospheric-oceanic oscillations are not effective tools for pinpointing seasonal precipitation patterns.
Outlook for the 2016-17 season
What’s in store for next ski season in the Tahoe Sierra? Last winter’s strong El Niño conditions have dissipated and winter 2017 is expected to have neutral conditions with neither warm nor cool water dominating sea surface temperatures. The lack of strong signals from the Pacific suggests a typical Tahoe winter with normal weather conditions. Professional forecasters, such as scientists with National Oceanic Atmospheric Association’s Climate Prediction Center, readily admit to the extraordinary challenges of long-range forecasts. For 2017, they are projecting equal chances for below, above or normal precipitation in our region. No confidence there.
The naked truth is that no one can predict seasonal weather conditions with much accuracy, but it doesn’t stop people from trying. It’s also a popular pastime on blogs and in local bars. Earlier this summer, computer models were suggesting that El Niño conditions would segue into a weak La Niña. That has not happened to the level expected. Cool neutral or weak La Niña events trend drier in California and wetter than normal in the Pacific Northwest. Based on prior episodes with these conditions, precipitation in the Tahoe Sierra comes in close to normal, ranging from 94 percent to 108 percent of average. Floods can happen in any given winter, but several extreme floods in the Truckee River watershed (December 1955 and 1964, February 1986 and New Year’s 1997) occurred in weak La Niña/neutral years.
Many people entertain themselves with the seasonal forecasts published in the “Old Farmer’s Almanac.” This venerable publication, founded in 1792, credits a proprietary forecast formula based on solar activity for its remarkable accuracy. However, multiple analyses by Jan Null, a former professional forecaster with the National Weather Service and now a consulting meteorologist, have shown the Almanac’s predictive quality to be marginal at best. Many years exhibit a skill level somewhere between 25 percent and 35 percent accuracy.
For winter 2016, Null reviewed 23 precipitation regions and concluded that the Almanac was accurate or “good” in 30 percent of the regions with 39 percent not good. Of 19 temperature regions compared, Null considered only 16 percent as good forecasts compared to 58 percent as “not good.”
As a weather historian, I don’t make forecasts, but if I was a betting man, 2017 looks to be an average winter, which in the Tahoe Sierra is pretty darn good. In most years a big chunk of our snow and rain comes from the moisture received from a half dozen big storms. As long as they show up, we’ll be fine.
Mark McLaughlin examines Tahoe’s winter floods
Tahoe historian Mark McLaughlin is a nationally published author and professional speaker. His award-winning books are available at local stores or at thestormking.com. You may reach him at [email protected] Check out his blog at tahoenuggets.com or read more at TheTahoeWeekly.com.