Where’s the Snow? Skiers Holding Their Breath…and Their Skis

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Both a Christmas card and recent email from my aunt and uncle in New Hampshire begged me to tell them when it would snow. My New England family is a big skiing group, but they seem to think I can put in a few good words and make it snow. Unfortunately, I can’t (but don’t tell my family!).

The current situation — a weather pattern spread across the past couple of weeks, this week and, to a large degree, next week — is frustrating skiers and ski resort owners across the country (report from NPR). Why? Both fall and early winter have been under the influence of La Niña and a positive phase of the North Atlantic Oscillation.

By Christmas, skiers and ski resort owners expect much more snow than this. Click for larger size. Image: NOAA

YourWeatherBlog has written about La Niña many times before  (here and here) and regular readers know this to be an unusual cooling of the eastern Pacific waters. This has global implications in that it changes typical temperature and precipitation regimes, making areas typically dry and warm, cool and wet and vice versa. One of the global impacts of La Niña is that it forces the jet streams much farther north than usual, resulting in a noticeable lack of winter storms in areas where they are expected (and now missed).

The typical winter pattern when La Niña is present. Click for larger size. Image: NOAA

Typical storm tracks, those not influenced by La Niña or its counterpart, El Niño, usually drive storm systems from their point of inception (the bitterly cold regions of northern Russia) into the Pacific and the Gulf of Alaska, then southeastward across the Great Basin, the Rocky Mountains and Plains of the United States, then northeastward — where they may cross the Great Lakes, push across the Mid-Atlantic states or they may target New England. Whatever happens, there is typically abundant moisture from the Pacific, the Gulf of Mexico, the Great Lakes (before they iceover) or the Atlantic Ocean. And of course, combine a winter storm system with abundant moisture and lots of snow is the usual result. That’s not what’s been happening for the past couple of months.

This upper-altitude weather panel highlights the jet stream as a blue arrow. Click for larger size. Image: Universal Weather and Aviation, Inc.

In fact, the pattern of the past week is the perfect example or what’s been happening. Storm systems are driven eastward along the Canadian/U.S. border where they are too far north to tap into humidity from the Gulf of Mexico; they must rely on Pacific moisture which dwindles with each day of the storm’s eastward progress. By the time a storm dips southeastward into the U.S. there may be locally heavy snows in the favored snow belts of the Great Lakes, but not until the storm can tap the Atlantic moisture will there be significant snow. That may, depending on the actual storm track, result in heavy snow for the Mid-Atlantic states, or for the Northeast or it may be confined to New England or — as is currently the case— southeastern Canada. The ski resorts in the Rockies are obviously unimpressed with a La Niña pattern. Those fortunate enough to be on the receiving end of snowfall are disappointed that it doesn’t last long enough.

Ski resorts are not totally out of business without significant snowfall. Many have no choice but to rely on snow cannons like this to lay down a layer of artificial snow. Improved technology allows these cannons to be more efficient while operating in a wider range of temperatures. Click for larger size. Photo: Wikipedia

But it’s not that these storm systems are missing the ski resorts altogether. ImpactWeather’s Fred Schmude adds more fuel to the fire:  “In addition to the storm tracks of a La Niña pattern, the lack of snow is primarily due to an atmospheric weather cycle known as the NAO.  When the NAO is in the positive phase the flow pattern moves along much faster keeping most of the really cold air over the far northern latitudes and at the same time decreasing the risk of major winter storm system over the U.S.  On the contrary, the negative phase of the NAO creates a slower flow pattern forcing colder air southward over the lower latitudes and increasing the risk of major winter storms and enhanced snowfall for the U.S. Additionally, storm systems influenced by a positive NAO are usually traveling too fast to let significant snowfall accumulate in any one place.”

Fred continues: “Last year at this time we were in a record negative phase of the NAO creating record-breaking snowfall in many areas. This year the reverse is true, with a much faster flow pattern and in some cases record-low snowfall totals for those same areas.  The outlook for January calls for the flow pattern to slow down by the 2nd week of the month which should allow much colder air from Canada to surge southward increasing the risk for major winter storms over the Lower 48 for the remainder of January and possibly into February, as well.  It’s still a little too early to tell if we’ll catch up to normal as far as snow totals are concerned, but long-range data favors a return to more normal winter weather by the 2nd week of January.

This is good news for skiers across the country, but especially good news for a certain family of skiers in New Hampshire.

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