100(ish) Days To Go & A Different Look At El Niño

We are now 100 days away from the officially announced “opening day” for Palisades Tahoe, which might include Alpine Meadows. For those that don’t typically count down the days, it’s usually the Wednesday before Thanksgiving that is assigned as opening day. But if you have been around for awhile, you know that date can get moved around based on natural snowfall, the ability to make snow and when other ski areas are opening. Alpine Meadows has opened as early as October 30th and as late as January 1.

For those of us that are really starting to get the itch to go skiing again, we won’t be waiting for our home mountain to open. Typically Mount Rose and Mammoth Mountain will open a good 10 to 14 days earlier than Alpine Meadows or Palisades Tahoe. The real diehards will get themselves to Colorado, where Araphoe Basin and Keystone race to be open first, often in October.

Based on the current extended outlooks, I am guessing that I will get some good use of my Mount Rose backup pass again before the season starts at Alpine Meadows. Mount Rose has not hinted at their opening date just yet. I miss the days where they targeted Nevada Day (aka Halloween) as an opening day. Often that meant starting the season on The Wizard or the magic carpet. They now open when it’s “almost top to bottom skiing” off of the Lakeview chair.

This Is A Different Look At El Niño

I know, I already wrote a piece on the El Niño phenomenon just about a month ago. In that piece, I debunked the notion that an El Niño year was a guarantee of a great ski season. Looking at the historical snowfall data for Alpine Meadows, some El Niño years were big years, but definitely not all of them. Some of our best seasons have been La Niña seasons. Back in July, we really only had historical data to look at, as the extended forecast models had not really become available yet.

Long range forecasting is not necessarily a super accurate science when it comes to predicting a particular storm. Normally when we look at the models, we are looking at a 16 day range. I often caution that anything beyond 10 days is “Fantasyland”, and from day 5 to 10 is “Maybe It Could Happen”. Inside of 5 days, the current weather models are very good.

But we are not predicting a singular storm here. We are looking at seasonal forecasts and they are a different story. Over the last 50 years, climate scientists have amassed a lot of data. We also have a lot more models that are generating seasonal forecasts. On top of that, there’s enough data centers out there to compile those models into ensembles. Those ensembles give us an average or “ensemble mean” that gives a picture that is worth more than tea leaves or how many acorns are being gathered by squirrels this fall.

So What Are The Models Saying About This Winter?

Since I am not skiing every day through the summer, I usually have a little bit more time to read stuff or watch Youtube videos to keep up on the trends. If you read here frequently, you know that my favorite source is the very notable Daniel Swain, PhD of WeatherWest.com. I will also mention Mark Finan here, who appeared as a weather forecaster on KCRA for decades. Finan has retired from KCRA, but still actively posts weather discussions on Youtube a few times a week. At the bottom of this post I will add links to their videos that inspired this article. I know there are some true weather nerds amongst our readers that will appreciate those.

Here’s the latest El Niño forecast for sea surface temperatures in the Nino3.4 region, which are the numbers you hear about the most.

Many of you probably need some tips on what you are looking at here. So here they are:

• This is the RONI, or Relative Oceanic Niño Index. In simple terms, our oceans are warming overall. So these numbers will seem lower that what you may have heard about for a “Super El Nino”.
• The graph shows the spread of about 50 ensemble members. The mean for all ensemble numbers is currently around 1.75°C. El Niño usually peaks around November and December. The mean of the ensemble members shows a peak of around 2.7°C. The previous recorded high was about 2.4°C. So, yes this is likely going to be the largest El Niño that any living person has seen. I have seen a few references to an even more super El Niño back in 1877, based on some ship logs recording the data.
• We should remain in an El Niño state through the end of ski season. That’s not always the way it happens.

It’s Almost Certainly Going To Be Wet

Up until this point most of the discussion about El Niño has been qualitative, stating only that it will be wet. We are just now having models looking at quantitative data, which attempts to assess how much wetter it will be. The GIF below shows the next four months as we head into winter:

By December, California is looking at a 100 to 200mm anomaly of rainfall, or 4 to 8 inches more than usual in that month. Without having a paid subscription for the ECMWF forecasts this is far as I can go. Check out Daniel Swain’s video below and you see that continues into early spring. It’s very likely to be a wet winter.

The storm door looks to open and stay open. In dry years we see continues battles between low pressure troughs that bring rain and snow, and the high pressure ridges that keep us dry. The GIF below shows the monthly pressure anomalies through December:

That low pressure in both the Gulf of Alaska and the interior U.S. is like a super highway for storms. Again, I only have limited access to the models without a very expensive subscription. If you watch Daniel Swain’s video, that storm door stays wide open through the ski season. There’s nothing that looks like the resilient ridging we saw the last two seasons.

Just for grins, below is a comparison of what the models call for pressure anomalies in December 2026, versus what they showed at this time last year for December 2025. Remember that no real storms happened until late December last year.

What About The Other Mark?

I’m talking about Mark Finan here, formerly of KCRA. The first part of his video parallels Swain’s. He also sees an almost certain very wet pattern and a wide open storm door through the winter months. But he also has some interesting discussion of El Niño and La Niña seasons. His primary point was to debunk those that say we will see massive storms this year. Much like I did in my last post, he looks at the historical data and compares it to El Niño or La Niña states. Here are his primary takeaways:

• Strong El Niño years almost always result in increased seasonal rainfall – as much as 40-50% more than average. This is the result to a lot of consistent storms with few breaks due to long term ridging.
• The biggest snowfall and flood events in California have mostly happened during La Niña years. That’s when we see the storms that keep Donner Pass closed for days on end and result in large scale flood events in California.

It’s worth watching Mark Finan’s video below. In case you thought the “other Mark” was my ski buddy Mark_The_Skibum, well he probably could have given the same conclusions as well. Sadly, Mark_The_Skibum is skipping an Ikon pass this season. We will miss having him at Alpine Meadows this season.

The Big Question Is Temperatures And Snow Levels

Actually it’s not a question. Nobody is saying this is going to be a super cold winter. The sea surface temperatures off the coast of California have been as much as 10°F higher than normal this summer. We should see some cooling, as upwelling of colder water has already been happening. But the models are indicating warmth as we head into winter.

The Pacific Northwest is likely going to struggle this winter. The 50 member ensemble, as shown by the ECMWF, shows that Tahoe falls into the “around average”. Hopefully we see that, as the wet and warm scenario is not good for skiers and riders. You can’t make snow if it’s raining. That was the story of last December.

There’s no sure bets. The models still give a nonzero percentage possibility we see a drier than average winter, which is not something we need. I’m hoping for good amounts of snow, as a healthy snowpack is better for California than a whole lot of rain that goes back out to sea.

We’ll keep watching the models as we countdown to winter. In some ways, summer is approaching an end. The Reno schools are back in session. The local schools aren’t far behind. Truckee Thursdays are done and other free music options only have another week or two left in their schedule. C’ya on the trails for now.