Most ski enthusiasts in the Pacific Northwest will think back fondly on the winter of 2010. Five months of massive snowfalls kept runs skiable well beyond the usual dates, much to the delight of ski resorts and skiers from the Cascades to the Rockies to the Sierra Nevadas.
In fact, I'd bet that Nina will be a most popular name for baby girls born this year in the western states... in honor of La Niña, that magical ocean-atmosphere phenomenom that graced the west coast with all that snow.
In a nutshell, the La Niña weather pattern starts with slightly lower surface water temperatures in the Pacific Ocean. Air currents blow cool, moist air across the western states, and voila! Powder on the summits from Tahoe to Sun Valley to Vail. Last year, during the 2010-2011 ski season, La Niña graced ski resorts with epic snow accumulations: a record-braking 524 inches in Vail, 783 inches in Snowbird, and 810 inches on Squaw Valley (that's over 67 feet - enough to bury a six story building!)
As we watch the skies and the weather reports, anticipating the first real snowstorm of the 2033-2012 season (any day now!) the questions most debated are whether La Niña will return this year: What kind of a snow year will we have? Should we plan a vacation to the mountains, or is this a good year to head to a beach?
La Niña rarely arrives two years in a row, so expectations for a repeat performance of the 2010-2011 ski season are guarded. However, ocean temperatures are still measuring within the range of La Niña, so we'll definitely see a solid snowpack over the western and northwestern states. The question is whether La Niña will arrive with the wild ferocity of last season. The answer depends on air pressure systems over the arctic, a factor which cannot be measured as easily as ocean temperatures.
The arctic air pressure systems can be negative or positive, according to the general pattern of air movement in the stratosphere. A negative phase in the arctic air sends frigid cold and raging blizzards across the northern hemisphere, which is what we experienced last year. A positive phase in the arctic air would tone down La Niña's effects, giving us a more moderate winter. Many meteorologists, including the NOAA and the Farmers' Almanac, are forecasting a slightly milder winter for 2011-2012 - still cold and wet with plenty of snow, but not packing quite the same punch as last year. In other words, La Niña lite!
So back to the vacation planning... mountains or beach? Odds are not good that La Niña will roll into town three years in a row, so this is definitely the year to head to the slopes and save the tropics for next year when snowfalls may be less than average. Anyone who missed out on the great conditions last year can stop kicking themselves, because Mother Nature is giving you a second chance!
Suzanne lives, writes, and plays in the mountains of Central Oregon with her family of adventure-prone boys.