Snow storm at Squaw Valley

Whenever I hear someone projecting an all time ski season or explaining why a winter was particularly epic I can almost always count on a few things popping up in the story.

  1. The person telling the story had or is planning to have a ripping season no matter what the weather brings.
  2. The person telling the story knows beyond a shadow of a doubt that there is some reason beyond the reaches of mere chance why the aforementioned season was or will be so damn epic!
  3. That reason (if not divine) must have something to do with El  Niño or La Niña.
  4. And lastly, the person telling the story probably doesn’t really have any idea what El Niño or La Niña actually does to the weather.
Big Fish

As far as I can tell the experts still don’t have this one figured out. I’m pretty sure I don’t either.

A few basic facts:

El Niño is characterized by warmer than average sea surface temperatures (SSTS) in the eastern equatorial Pacific ocean. (Warming of at least 0.5 C or 0.9 F)

ENSO El Niño
El Niño, warmer surface temps in the equatorial Pacific

La Niña is characterized by colder than average sea surface temperatures (SSTS) occurring in the same region . (Cooling of at least 0.5 C or 0.9 F)

La Niña, cooler surface temps in the equatorial Pacific
La Niña, cooler surface temps in the equatorial Pacific

The Pacific ocean is a huge heat sink and when the surface water temps change the air temps are affected.  The “Southern Oscillation” portion of the ENSO (El Niño Southern Oscillation) refers to the  effects on atmospheric circulation. El Niño generates more atmospheric convection, and higher air pressures over the tropical Pacific while La Niña usually produces lower pressure conditions.

The “patterns” oscillate sporadically, shifting every 3-5 years or 2-7 years or some other weird interval depending on what you read.  If the anomaly lasts only a few months it is considered El Niño or La Niña conditions. If it persists for a longer period of time it becomes an “Episode.” For the last couple of decades we have experienced a higher than average recurrence of El Niño cycles. Some people have pointed to global warming to explain this. Either way it seems like everyone is pointing to El Niño or La Niña to explain the weather. Last year we experienced dominant La Niña conditions and according to NOAA forecasts we may be entering a La Niña episode. Will we get more snow?

Eric Bryant Skiing Pow, Powder
Skier: Eric Bryant

The answer is nobody really knows. It’s frickin’ weather.

The affects of this anomaly are widely studied and poorly understood. One thing that seems to be somewhat reliable about La Niña conditions is a baller winter for the Pacific Northwest. Shasta to Alaska tends to get hammered during a La Niña, I’m not gonna argue that point, but does it make any difference for Tahoe?

El Niño pulls wet storms into Southern California and generally increases the temperature of storms that reach the Sierra Nevada.  More water less chill. If other parameters line up we can get dumped on, but if it’s too warm we can get rained on. I remember a time when every big dump was attributed to “El Niño” but now it seems like “La Niña” is taking the cake.

jamie blair squaw valley powder day

skier: Jamie Blair. photo: skier666

Tahoe’s latitude seems to put it in between the regions most affected by El Niño/La Niña cycles. Most weather experts say its a bit of a wash for the area. I.E. we can experience good or bad seasons during either cycle and there are a lot of other factors involved.

Call it whatever you want, if the snow this year is anything like it was last year I say bring it on! La Niña, El Niño, who knows, just make it snow!


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