Greetings skiers from Ski Oregon! I’m happily looking forward to again providing you with what I hope are many powder alerts for the upcoming season. As you may or may not have seen, there have already been dustings of new snow on Mt Bachelor and Mt Hood, and I’m sure in the mountains of NE Oregon too. Which gets the chops licking and the visions of fluff flying in your face going, but what might we be looking at for the upcoming season? Here are my thoughts:

First, let me get the Farmers Almanac out of the way. OK now I can type on my keyboard better. Ha. Seriously, the venerable publication of recipes, balms, salves, concoctions, and all things Americana, is forecasting a cold dry winter for the Northwest. The Almanac’s accuracy is not the greatest, but beyond that, I don’t see any big indications for that type of winter here. The best scenario for a cold dry Northwest winter is a STRONG La Nina, and that seems highly unlikely this year, as you can see in the graph below.

The climate driver that we’re most aware of is the ENSO, which stands for “El Nino Southern Oscillation”, which is the technical name for the phase or state of the weather and ocean conditions in the tropical Pacific Ocean collectively known as El Nino, La Nina or No Nino. You’ve probably heard of those. Ha again.

We’ve got a No Nino going now that is expected to continue into Spring. That is, no El Nino, no La Nina. And that’s not bad news at all for snow lovers.

We’ve seen some very good mountain snowpacks in No Nino years. Below is a graph of the likelihood of a El Nino, No Nino or La Nina for the upcoming season. ASO means August-September-October and so on.

And here is a link to the Columbia University website with more details on the the graph:

http://iri.columbia.edu/climate/ENSO/currentinfo/figure1.html

No Nino years have also produced some big valley snowstorms. In Portland, we haven’t had an above average snowfall winter since “Arctic Blast” hit us in 2008-2009. I bring this up because that stretch is likely to end soon, and usually when Portland gets snow, the ski areas get a large helping of powdery goodness.

Another climate driver that has an impact on Northwest winter weather is called the Pacific Decadal Oscillation, or PDO. It’s similar to ENSO except it is defined by temperature anomalies in the North Pacific. When the PDO is negative, or in the cold phase, we tend to have cooler than average winters. The PDO is negative now, so if that trend continues, it may be an indicator for a cold winter. The PDO doesn’t have a good signal for wetter or drier than average here. That said, the PDO was also in its cold phase last year, and unlike El Nino/La Nina, which typically last for 6 to 18 months, the PDO changes phase, it seems, every 20 to 30 years.

I don’t think it’s as good an indicator of upcoming winter weather as ENSO, but it’s still interesting to consider.

Of course, a good ski season is not defined simply by how much snow falls in winter, but also by WHEN it falls. Last year we had average snowfall, but most of it came in November and December and a lot of skiers didn’t feel it was a great season after that.

The good news for Northwest skiers is that No Nino winters tend to bring frequent storms. That can mean frequent refreshment of the snow on the slopes. All it really takes is about 4 inches of new snow to put a good new skiable layer on the snowpack.

So, bottom line, I see no reason to think this WON’T be another very satisfying ski season! Let’s get ready to ride!

Matt Zaffino
KGW Chief Meteorologist