TAHOE/TRUCKEE and#8212; Exceptional snowfall last month gave regional resorts excellent conditions well before the all important Christmas-New Year holiday period. The series of storms that originated in the Gulf of Alaska combined with very cold air to blanket the Sierra with the most November snow in recent memory.

The numbers from November are worth reviewing. Several ski areas reported the most snow ever for November snow accumulation. Alpine Meadows declared it the single biggest November snowstorm in the resort’s history, which started keeping monthly totals 40 years ago in 1970. Tahoe resorts picked up from 6 to 11 feet of powder during the month. With the best pre-Thanksgiving snow conditions in decades, skiers and snowboarders flocked to resorts that opened with top to bottom skiing and most lifts turning.

Despite the epic snowfall in the mountains, November rainfall totals in lowland California were decidedly unexceptional. San Francisco measured just over 3 inches, about 94 percent of normal. Sacramento was better at 109 percent above average, but Redding up north came in at just 56 percent of its normal November total. Surprisingly, it was Fresno in the San Joaquin Valley that showed the greatest monthly anomaly with 164 percent precipitation.

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Cold air surging into California behind the frontal passage spawned a damaging tornado in Shingle Springs, and tied or broke record low temperatures up and down the state. The Thanksgiving Day cold snap dropped the thermometer to 42 degrees in San Francisco, tying a record set back in 1892. In Oakland, the temperature plummeted to 36, shattering the old record by six degrees. Subfreezing temperatures in the Central Valley threatened to damage the state’s billion dollar crop. Temps in the Sierra were positively frigid: South Lake Tahoe set a new record low at minus 8; and Truckee tied its own record at 12 below zero.

At the Central Sierra Snow Laboratory (CSSL) near Donner Pass, November storms are important as they usually produce more than 10 percent of the average yearly total, with 48 inches of snow and enough rain to total more than 6 inches of precipitation. (Precipitation is rain combined with melted snow.) During November 2010, CSSL hydrologists measured 97 inches of snow, the most ever recorded there since the lab was established at the end of World War II. But a quick study of the weather records indicates big November snowfalls may have been more common in years past. During the two decades between 1885, when 136 inches of snow buried Norden near Donner Pass, and 1905, when 78 inches fell, there were seven Novembers that at least 5 feet was recorded.

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Moving forward, December is an important month when it comes to building up the snowpack and replenishing regional watersheds. The CSSL averages more than eight inches of precipitation during the last month of the calendar year (16 percent of the yearly total) and nearly 70 inches of snow.

This winter is off to a strong start; precipitation in October was 253 percent above normal and November dumped all that snow. The 8-Station Sierra Index indicates that precipitation in the Northern Sierra is running at 167 percent of average for this time of year. Interestingly, this winter’s precipitation plot line on the graph is closely following the plot line from 1982-1983, the wettest year on record. During the winter of 1983, nearly 90 inches of precipitation inundated the region, including 56 feet of snow measured at the Snow Lab.

and#8212; 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 mark@thestormking.com