Anticipation! Anticipation!

There is a classic tune that encapsulates what is going on in the heads of skiers every fall: “Anticipation! Anticipation!” (Carly Simon by the way is the one that does a much better job of it then the version I just belted out). What kind of winter will it be? A big one? A drought? A normal winter? When will it arrive? And when will it end? And will I have to shovel the dang roof again? Of course everyone has their theories.

Some folks tout active squirrels as a sign it will be a big winter (seriously, has anyone ever seen a non-active squirrel? They always look like they consumed way too much Red Bull). Others point to the especially big pine cones to indicate that we better batten down the hatches. Then of course there is the always accurate information source: what color the leaves are and when they fall down.

A more reliable authority is the Old Farmer’s Almanac. Here is what they say for this winter:

“A strong El Niño means winter will be wetter than normal, with above-normal mountain snow…the stormiest, wettest periods will be in early and late January, early to mid-February, and mid-March. There will be a white Christmas across the Sierra Nevada mountains, but not in the valleys or along the coast,” (Wow, big surprise not a white Christmas in the valleys or along the coast of California. They are really sticking themselves out there with that prediction).

It turns out the National Weather Service (NOAA) as well as Open Snow, pretty much agree with the Almanac (or more likely the other way around).

Here is what the National Weather Service has to say:

“During the spring months, the pattern quickly reversed from a La Niña phase into an El Niño phase. El Niño has continued to strengthen over the course of the summer and is a near certainty to remain in place through the winter of 2023-2024. In fact, NOAA’s latest model-based outlook projects a greater than 90% chance of El Niño persisting through the winter of 2023-2024.”

Ok, so it’s going to be an El Nino. Sounds impressive. But what does an El Nino really mean?

The Weather Service says “strong El Niños result in roughly equal chances of above or below-average snow seasons. In other words, stronger El Niños are usually better than weak or moderate El Ninos in this region. However, temperatures are typically warmer than average across the Pacific Northwest during strong El Niños, which could indicate that average snow levels during storms are higher than usual.”

And then of course the much needed caveat from NOAA:

“Winter outlooks contain an inherent degree of uncertainty since so many factors in the atmosphere are not predictable months or even weeks in advance.”

Long range predictions in other words are really hard, but I’d like to speak up for our forecasters. They really are uncannily accurate when it comes to what is going to happen in the next week, and fairly reliable up to ten days. The problem forecasters sometimes confront is that their words are frequently taken out of context by media and social media and then turned around and used against them. For example, a not uncommon forecast for our region would be: 6-12 inches at lake level, with 1-2 feet at 8000 feet with a slim chance of up to 3 feet. The news programs take this and flood the media with: “Three feet of snow expected at Tahoe.” Then when we get a foot, everyone is disappointed and says it didn’t snow as much as they predicted.

Now let’s take a look at what our friends at Open Snow have to say. Our local Open Show guy reviews National Weather Service info and lots of other sources to fine tune his forecast for what it means for skiers. Here is the Open Snow take on the meaning of an El Nino targeted towards Palisades Tahoe.

“5 out of the 10 (50%) of the El Niño seasons produced above-median precipitation near Palisades Tahoe as of May 31. For snowfall, after looking back at the 10 significant El Niño years and comparing them against the 50-year median snowfall as of May 31 at the Snow Lab, I’ve found that the median snowfall ends up around 419 inches for the 10 significant El Nino seasons compared to the 50-year median of 372 inches.”

So what I think the experts are trying to say here is we have a coin toss whether this will be an above or below median precipitation year, with maybe a slight advantage to the big winter side of the coin. We will know it when we see it. I’m sure many of us after the mega winter we are still recovering from would appreciate a Goldilocks winter that is not too big and not too small, but right in the middle. Something we could call normal.

Ah normal, such a misunderstood word. Let’s define three important terms that we hear often regarding the size of a winter: Normal, Average and Median.

First, median in the context of what we have been talking about means that 50% of the years had bigger winters and 50% of the years were smaller. While folks like to use the term normal to refer to something that is common and usual, it actually means the same as average. And in the Sierra Nevada especially we need to remind ourselves that the average amount of precipitation is based on some really big winters, and some really dry winters. In fact, it’s not overly common to see one super close to the “average” although that might be nice. A graphic representation of this principle can be found at the back of the Truckee River dam. There on display is a chart showing the level of lake Tahoe over the last 120 years. The lake fluctuates back and forth between 6222’ and 6229’ so often and so quickly that the graph looks like my heart rate skating up Nose Dive.

Now that we have been dusted with a dash of snow it is time to prepare for winter, and check those ten day forecasts, because those will tell you what is really going to happen.