Weather Window | Tahoe winter’s final wrap
May 22, 2013
TAHOE/TRUCKEE, Calif. — If the topsy-turvy winter two years ago bummed you out with its lack of precipitation and water runoff, you might not want to read the rest of this article. Whereas the 2012 water year set records for lack of snow and rain in the first half of the season, 2013 has been a mirror image with a huge start in the first two months and nothing significant for the rest of the year. With resorts closed for the season and the bulk of the year's rain and snow already in the bucket, it's a good time to look back at the extremely unusual 2013 winter weather pattern.
This is how crazy last winter was. In the Northern Sierra, November and December was the ninth wettest of record for the combined months. But then, in a stunning pattern reversal, the next three months — January, February, and March — were the driest on record for the region.
Statewide, the Jan. 1 snowpack stood at 140 percent of average to date. By April 1, the time of year when the snowpack statistically reaches its greatest water content, surveys indicated a snowpack at only 42 percent of average for the date. Kelly Redmond of the Western Regional Climate Center said the extreme flip-flop was like Dr. Jekyll and Mr. Hyde, an allusion to a man with polar personality disorder depicted in Robert Louis Stevenson's classic 1886 novella, "The Strange Case of Dr. Jekyll and Mr. Hyde."
Off and running
The season started early with a huge October snowstorm that dumped nearly four feet at Alpine Meadows. In response, regional resorts fired up their snow guns to get their chairs turning early. At the end of November, a media-dubbed "California Superstorm" doused the mountains with significant amounts of rain at elevations below 7,000 feet. Heavy wet snow fell on the upper slopes of Tahoe resorts and laid down a healthy base for the upcoming ski season.
Several weeks later during the Christmas-New Year holiday vacation, a series of cold, powerful storms pounded the region with heavy snow. At his home at 6,700 feet in Carnelian Bay, local weather observer Ken Wallace had measured a hefty 23 days of snow by Dec. 30 for a total of nearly 9.5 feet. By New Year's Day, Squaw Valley's upper slopes had picked up nearly 21 feet of snow. And even the lower mountain, which had lost much of its base during the early December rain event, had received another 12 feet of snow.
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It was the best start to a winter since the epic 2011 season, which ranks as the ninth snowiest of record at the Central Sierra Snow Laboratory (CSSL). It was also the best early start for precipitation since the epic winter of 1983, the all-time wettest season in the Northern Sierra.
The storm door closed
But then the storm door slammed shut from January to April as Pacific weather systems detoured around the Tahoe Sierra. It was an unprecedented dry spell for the Tahoe-Truckee region. Tahoe City received only 2.68 inches of water during the period — statistically the wettest time of year that averages more than 16 inches of precipitation — which set a new record as the driest three-month stretch since measurements began in 1910. According to Bay Area meteorologist Jan Null, San Francisco's January through April rainfall total of 3.32 inches was the least amount since measurements began in the 1849 gold rush.
As of May 13, Randall Osterhuber, manager at the Snow Lab had measured only 17.8 feet of snow for the season, which ranks as the fifth least snowiest winter there since 1878. For more perspective on how little snow fell last year, winter 1881 ranks as the all-time least snowiest on record at Donner Pass with 12.8 feet, just 5 feet less than 2013.
At the beginning of May, the Lake Tahoe Basin snowpack was basically nonexistent, at 4 percent of average for that date. With little snow left on the slopes Big Blue is forecast to rise only a few more inches to its high point, but fortunately water storage in Tahoe is 93 percent of normal. Reservoir storage in the Truckee River watershed is a healthy 101 percent of average, but the streamflow forecast for the Truckee River this summer is only 38 percent of average at the gaging station at Farad, Calif.
Dry winters like 2013 give Sierra water managers fits as they try to fulfill deliveries to downstream water rights holders. And coming on the heels of a similarly dry winter in 2012 only makes the job more challenging.
Tahoe historian Mark McLaughlin is a nationally published author and professional speaker. His award-winning books are available at local stores or at http://www.thestormking.com. You can reach him at firstname.lastname@example.org. Check out Mark's blog at http://www.tahoenuggets.com.