A climatic event developing in the equatorial regions of the Pacific Ocean could spin warmer winter weather north to Alaska.
Good news for Southcentral Alaska residents worried about the region running out of natural gas to meet heating demands in a cold snap, maybe. Bad news for skiers and Bush residents looking to the freedom to travel winter trails by snowmachine, maybe.
Weather forecasters caution that long-term climatic predictions -- anything more than a few days, really -- remain inherently unreliable. In other words, don't bet the house on this being a warmer, wetter winter in Alaska.
All anyone really knows is that brewing in the Pacific some 5,000 or so miles south of Alaska now is what is technically called an El Niño-Southern Oscillation, or ENSO -- what most people know simply as "El Niño," a pooling of warm water off South America. This water usually spins northward on the prevailing ocean currents to warm the entire Pacific Coast of North America.
Early Spanish speakers in America labeled the phenomenon El Niño, a reference to the baby Jesus, because the warming brought on by equatorial waters moving north is usually first noticed on the continent around Christmas.
What El Niño usually means for Alaska is a warmer, wetter winter, but there are no guarantees.
"If El Niño conditions...continue to develop as the climate modelers are indicating" -- a big qualifer there -- "then the probability that Anchorage evirons are warmer than the long-term normal is reasonably high,'' said John Papineau of the National Weather Service. But he offers no guarantee.
Most El Niño years in Alaska have been warmer than normal, but not all. In the El Niño year of 2007, for instance, Fairbanks was almost six degrees colder than normal. Most other locations around the state saw a similar chill, although Southwest Alaska was just a tad warmer than normal.
Much the same happened in the El Niño winter of 1995. Anchorage, Fairbanks and most of the state went cold, but the Bethel area was a bit warmer. If one traces weather records all the way back to the 1960s, a year can even be found when Fairbanks was pushing 10 degrees colder than normal in what was supposed to be a warm winter.
But all of those cold El Niño winters are considered anomalies.
The norm for "the child" is a rise in temperature and moisture in Alaska. In what form the moisture falls along coastal Alaska is, however, another big unknown. The Alaska coast is fickle. A temperature difference of just a few degrees is all that's separates soggy from white.
"Keep in mind,'' Papineau said, "that the enhanced precip during the winter does not necessarily translate into more snowfall as the frequency of warmer snowfall events is also increased. This is especially true along the Gulf of Alaska where temperatures are often near freezing.''
Translation:
If it warms up enough for Anchorage to go all Seattle-like, the skiing sucks.
The happened in the winter of 2002-03. Less than 40 inches of snow fell that winter, less than two-thirds of the norm. People were hiking when they would normally have been skiing or snowmachining. When it did snow, it rained shortly thereafter to wash the snow away.
But it doesn't always work out this way. The winter of 1994-95, another El Niño winter, brought more than 120 inches of snow to Alaska's largest city. That's 10 feet. People were sometimes so busy digging out they didn't have time to ski or snowmachine.
So, to prepare for this winter if you live in Anchorage, you should probably either invest in a good raincoat, or a snowthrower or snowplow for your truck, or all three. And then, too, you might want a good parka in case El Niño pitches another anomaly.
Because the truth is that all history does is enables weather forecasters to make a good guess at what El Niño is likely to bring north. They don't really know. They can't. The global climate is hugely variable and humans are a long, long way from figuring out exactly how it works. Here's about all they really know for sure:
Anchorage winters have, for reasons not perfectly clear, been getting generally warmer since the early 1900s. There used to be 20 to 30 days each winter when the temperature went below minus-10 degrees. In the last couple decades, there have usually been only five to 10 days when that happened. So a mild winter in Anchorage this year would be largely in keeping with the new normal.
Elsewhere in Alaska, however, there's not much sign of moderation from the well-known norm of the frozen North. Barrow shows no trend toward milder winters. It has been oscillating between 45 to 90 days of minus-20 cold for almost 100 years. The same for Nome, which has been in the range of 60 to 90 days below zero since near the Gold Rush days.
In that El Niño winter of 2002-2003, when Anchorage temperatures for November to March averaged near 29 degrees (the norm is about 20), Nome had about 60 days below zero, which is pretty much a normal winter there. If there is any such thing as normal in Alaska.
"The final caveat,'' Papineau said, "is that since Alaska is so large, some regions are impacted differently than others during El Niño....Hence once should not imply that the entire state is going to be impacted in the same way or 'degree.'''
If, indeed, anyone really knew how the state was going to be impacted.
Contact Craig Medred at craig_alaskadispatch.com