Winter is only a few short weeks away, and we are all starting to wonder what our ski and snowboard season will look like here in Tahoe. Will we see another big year with more powder days than we can handle? Will it be an average year? Or will it be another drought year, where we spend more time on our mountain bikes than snowboards? Long range weather forecasts are tough for meteorologists, however that doesn’t stop us from reading winter predictions. So what will Tahoe look like this winter?
La Nina vs. El Nino
Before we get in to looking at what we will see this year, let’s talk about ocean temperatures. Ocean temperatures, specifically the Pacific Ocean, have a strong influence on winter storms in North America. La Nina periods are those where the surface temperatures near the equator in the Pacific Ocean are cooler than normal. El Nino periods are just the opposite, when equatorial surface ocean temperatures skew on the warmer side. These surface temperature changes are due to the pattern of trade winds. The normal track of the trade winds bring cooler upwelling water towards the equator, thus the cooler temperatures. When these winds slacken, as they tend to every three to seven years, the equatorial pacific water warms up thus El Nino conditions.
What Does That Mean for Tahoe?
During a La Nina period, weather tends to be colder than normal in the northern US, and milder in the South. Historically, during El Nino episodes Tahoe sees a wetter than normal winter. Neutral ocean temperatures typically mean that the West has an equal chance of either above or below average precipitation. The ocean temperatures influence the storm tracks and intensity. This is why in the early season, the focus is all on the equatorial pacific ocean temperatures.
Early Season Snow
According to OpenSnow reporters, Donner Summit recorded the 3rd wettest October since 1870 in 2016. Precipitation in the early season is a good thing, especially after such a dry summer. November, on the other hand, has seen very little precipitation and warm temperatures. This has driven some ski resorts to push back their opening day to Thanksgiving weekend. The warm and dry November is not a cause for concern for the whole ski season, as weather is an unpredictable beast! The best forecasters will tell you that even with all their forecast models, you really can’t predict exactly what will happen with each storm track. Especially this early out.
Last year, early season predictions called for a Monster El Nino. The hype was so big, and we were all expecting a very wet year and over average snowfall. We did see El Nino conditions, but most of the storms that occurred tracked further north than what Tahoe powder-hounds wanted. Overall, Tahoe received snowfall amounts on par with our average. Here are some of the predictions we are reading for the 2017 winter:
Powderchasers is calling for a trend of neutral ocean temperatures, thus an equal chance of above or below average snowfall.
The Farmers Almanac is predicting temperatures and rainfall to be below normal, with below normal mountain snows. “The stormiest periods will be in late November, mid-December, and mid-January. The coldest temperatures will be in early and late December and mid-to late January.”
The early forecast from OpenSnow on our Tahoe winter was we were to receive 85 – 92% of average snowfall. We might see an ENSO neutral condition (neither El Nino nor La Nina conditions) for this winter. “It is a difficult Winter to forecast and it could go either way” says the Tahoe snow reporter, “and an average winter of 400-500 inches on the mountains is still a great winter.”
NOAA is stating that there is a 70% change that a La Nina will develop during our fall, and it is slightly favored to persist during the upcoming winter.