After a frothy start to the ski season with early resort openings and talk of El Niño, many of us began wondering if this could be the epic year we’ve been waiting for, or if it would turn out to be another false start that begins with a bang and fizzles in disappointment.  The bay area saw some unusually heavy rain in October, followed by a cold snap and a series of storms in November that brought dryer snow to the mountains. The snow pack was beyond adequate for some of the best holiday skiing in recent years, but then at the end of December, the Department of Water Resources reported that the water content of the snowpack was only 85% of normal.

Now the storm window is opening up again, and if you’ve been checking the weather forecast, you’ve heard we’re in for a week of big-time storms (ten feet or more at the highest points!) hitting the Northern Sierras in succession.

To find out what it all means for the Sierra forecast and where El Niño comes in, I spoke with Bill Martin, Chief Meteorologist at KTVU Channel 2.

First of all, Bill explained, there are different degrees of El Niño.  The strength of an El Niño (weak, moderate, strong) is correlated with sea surface temperatures in the equatorial Pacific ocean.  So far, we’ve been in a moderate El Niño which has recently strengthened, with sea temperatures reported by NOAA at 1.8 degrees Celsius above normal as of January 16th.  A weak El Niño often means dry conditions in Northern California, and wet in the South.  A strong El Niño can bring heavy precipitation to Northern California.  However, some of the biggest, wettest storms have happened in non-El Niño years, when the jet stream carried cold arctic air down to warmer climates causing big snowfall dumps.  With a moderately strong El Niño, we have potential to see big storms, albeit less continuously wet than with a strong El Niño.

Although the forecasting models disagree on the eventual peak strength of this year’s El Niño, Bill pointed out that very strong El Niño years like those in the early 1980’s and late ‘90s aren’t necessarily the best ski seasons.   They’re characterized by wet snow and sometimes rain at lake level.  The heavy snowfall can lead to road closures and avalanche danger, making it difficult to even get on the slopes.  While very wet Pacific storms can be great for the water table, cold Northern storms make for better skiing.  He expects that we’ll see a combination going forward this year.

Bill pointed out that this is already a good ski season with consistent snow coverage, and a good base layered with re-frozen snow.  So check the weather advisories, and then get out there and enjoy it!