La Niña has returned! La Niña is the weather condition that brought us an epic winter last season resulting in record sales and participation. On September 8th, the National Oceanic and Atmospheric Administration announced that La Niña conditions were back after a four month hiatus and were expected to strengthen throughout the 2011/2012 winter. The coming winter may not be a carbon copy of last season, which brought in almost 30% higher than average snowfall and had enough snow on the 4th of July to gain 50,000 skier/rider visits, but it is excellent news for most regions. Generally speaking, a La Niña winter brings an active northern Pacific storm track with a less active southern Pacific storm track. But persistent storminess in the Northwest and Northern Rockies could result in the threat of flooding in lower elevations and enough mountain snow, when combined with temperature fluctuations, to result in a deep and unstable snow pack.
La Niña by Region:
Rocky Mountains/Colorado – During La Niña winters the central and northern Colorado Mountains tend to receive normal to near normal moisture. But the southern part of the state and the desert Southwest tend to get less than average moisture during the winter. Overall, La Niña should bring average snow levels and temperatures to the Rockies but, the mountains may have some extreme cold snaps and wind will be a persistent issue this winter. Bora wind from the Yukon will bring cold and dry wind to the Rockies and the Chinook winds will bring warm and damp winds from the south this winter. Some of the coldest weather on record in the Rockies has been recorded during La Niña years and 2012 could have some record setting cold days. The Wasatch Range in Utah, generally considered the western edge of the greater Rocky Mountain Range can expect another excellent season with above average snowfall.
Southwest – La Niña brings dry winters to the Southwest, and there are no exceptions to this over the past 65 years. This is not good news for the drought ravaged region. La Niña brings much more consistent consequences in the Southwest. Arizona, New Mexico, Texas, Southern Colorado and Southern Utah will have moisture challenged and warmer than average winters this year.
Pacific Northwest – Lower than average temperatures and higher than average precipitation again this winter. This region will get a wealth of snow this winter as La Niña drives colder temperatures and moisture off of the Pacific resulting in higher than average snowfall.
Northern California/Nevada – The Sierras – La Niña tends to be tricky in this region due to a phenomenon known as the Pineapple Express. The Pineapple Express, a relatively common weather pattern that brings southwest winds to the Pacific Northwest or California along with warm, moist air is likely this winter. The name comes from the source of the moisture: The tropical Pacific Ocean near Hawaii, where pineapples are grown. The Pineapple Express sometimes produces days of heavy rain, which can cause extensive floods. The warm air also can melt snow in the mountains, further aggravating flooding. During the colder parts of the year, the warm air can be cooled enough to produce heavy, upslope snow as it rises into the higher elevations of the Sierra Nevada or Cascades.
Southern California – Expect drier than average conditions and higher than average temperatures in Southern California this winter. Keep in mind that the Pineapple Express could bring heavy upslope snow to California resorts like Heavenly, June Mountain and Mammoth that will drive consumers into snow sports retail this winter despite warmer and drier local conditions. Resorts located further south including Mountain High and Bear Mountain will have plenty of snow for their parks but may experience warmer and drier than average conditions during the 2011/2012 season.
Midwest – Colder than normal temperatures and heavy lake effect snow for northern Wisconsin and the UP of Michigan, Northern Indiana, Northern Ohio and other areas in the mid-west (and northeast) normally effected by lake effect snowfall.
Northeast – NOAA’s forecast for the Northeast is more of a non-forecast with equal chances for above or below average snowfall. Look for a winter that is much like last winter with colder temperatures and the potential for severe ice storms. There are exceptions to this forecast for regions of Pennsylvania and New York that enjoy lake effect snowfall.
Mid-Atlantic – The mid-Atlantic region including Southern PA, MD, VA, and NC will be defined by unsettled winter weather including warmer than average temperatures and mixed precipitation events that could bring ice, snow, sleet, and rain in a single storm. Mid-winter warm ups, and general variability in the temperature will be the norm for this region on the cusp of the La Niña temperature gradient.