Tahoe Backcountry Snow

Backcountry obs.:

Snowfall from last week’s storm has melted in all but the highest north facing areas around Tahoe. Trail conditions are superb with minimal dust, tacky, springy dirt, and water running again in the most established stream beds. Cruising the trails, it’s impossible to ignore the pungent smells of fall: decaying leaves and wet ground. Fall colors are also more stunning than they’ve been in years with aspens, cottonwoods, and even maples, showing their most vibrant yellows, golds, and oranges. Right now a trip into the backcountry is a total sensory experience.

Weather and forecast thoughts:

What a week ago looked like a solid signal for significant precip., has now fizzled into a dreary weekend of rain showers, cool temps, and blustery conditions. Models throughout the week have trended drier and warmer, pushing the bulk of the energy to our north into the Pacific NW.

Here are some visuals from the models:

For the coming weekend, expect rain on both days with the majority falling Sat. and Sat. night. Strong SW breezes will accompany the rain on Saturday, then back off on Sun. as precip. tapers to showers under cloudy skies. Highs both days will be raw: mid 40s at lake level. Some snow can be expected on the highest passes and peaks above 8500′ with just a few inches of accumulation expected. In total, that Tahoe Basin has a 50% chance of receiving up to .50″ of liquid with the highest chances and highest amounts favored the further north you travel.

Behind this system high pressure returns with sunny skies and above average fall temps going into early November. Winter must wait, but in the meantime, the coming rains ensure that a stellar autumn continues.

Nearly a week ago the season kicked off with a bang as the first significant snowfall blanketed the Tahoe Sierra. Snow totals from a few inches to over a foot in the Mt. Rose and Carson Pass areas blanketed the region. By late Tuesday, a few clips of folks ripping powder in the Mt. Rose area surfaced on the interwebs.

The October 13-15 storm was a quirky one that at one point around late afternoon on the 14th, brought snowfall and 33°F to lake level in South Lake Tahoe while it was around 6° warmer and raining in Carnelian Bay. South and Eastern parts of the Basin also picked up higher snow amounts than the traditional magnets on the NW side of the Basin. The Eastern Sierra from Ebbetts Pass down to the Mono Recesses picked up feet of snow while points north of Tahoe generally received less than a foot.

What happened? A look at the storm from the 14th is revealing. Here are the winds from the lower atmosphere.

Bands of rain and snow drenched Tahoe for most of the day of 10/14, but tracked in mainly from the SE. Looking at the position of the low, it’s easy to see how points south received more moisture with the flow off the Pacific bringing more rain and high elevation snow to the Central and Southern Sierra, while Tahoe received more of the wrap-around effect, with the Carson Range benefiting from enhanced upslope flow.

Since late week, skies cleared and temps have warmed considerably into the 60s around the lake, melting most of last week’s snow. Shady N and NE aspects above 8000′ still hold some residual crusty snow, with facets developing underneath.

It’ll be worth remembering these patches should they hold on until the next snow. Looking at the models, a potentially more potent storm with a solid moisture plume may impact the area next weekend, 10/24-10/26.

Until then, pleasantly warm, sunny days and cool nights are on tap for the coming work week.

1709 wx. at 6350′ in Carnelian Bay: Moderate rain / 49.6°F / 49.1°F dew point / 98% RH / total daily rainfall: .64″

Weather and forecast thoughts:

October 1 rang in the new water year with a few hundredths of an inch of rain and the wet parade continues to this writing with more than 1/2″ falling so far today. The bluebird beach days of late summer have recently been interrupted by cool, rainy and unsettled weather. Fall is quickly descending upon the Sierra and the first snows of the year are just around the corner.

By Sierra standards, it was a great summer. Choking wildfire smoke and insufferable heat never really materialized. Temperatures averaged slightly above normal and while generally dry in the first half, the monsoon did eventually kick in, bringing rounds of wet afternoon thunderstorms in July and August. Just as trails were reaching peak dustiness, the sky provided relief. It’s been downright pleasant, a far cry from the searing heat and weeks of smoke from summers passed.

Looking ahead to ski season 2026:

“Long range models are too good to ignore, but too unreliable to use.”

Over the past year I’ve been back in school completing a forecasting program at Penn State. Of all the exciting things I’ve learned, one that gives me the most pleasure is encapsulated in the above quote from someone over the years. Even with all the collective understanding of the science and new tools at our disposal, long range forecasting remains difficult. Accuracy diminishes significantly beyond five days, not to mention five months out. What is available does help to paint a general picture of what’s out there. Current technology allows us to see oceanic conditions and atmospheric circulations. But the atmosphere and its interplay with the oceans is chaotic. We simply don’t have the capacity to measure every air parcel of the atmosphere at every point in time, and then plug those observations into predictive models. What a joy to be so humbled and have so much yet to discover!

Looking at what’s on the table for the coming year, the tropical Pacific currently shows signs of a weak La Niña developing.

Despite the dramatic headlines, there is very little, if any, correlation between La Niña and wet or dry years in the Sierra. Take a look at the below graph showing Dec-Feb precipitation in El Niño, La Niña, and ENSO neutral conditions dating back to the mid 30’s.

It’s all over the map.

In the chaos of the atmosphere, ENSO is only one background variable of many different atmospheric circulations and oceanic conditions that can affect what we end up receiving in the Sierra. While it often receives so much attention – and rightly so for many parts of the world – the data don’t seem to bear out any strong signal for the Sierra.

Here’s another table to illustrate the point. The two biggest years of the past few decades actually came in during ENSO conditions similar to now that inspired more yawns than screams.

And here are some charts showing how ENSO conditions similar to what we’re currently experiencing play out seasonally for temperature and precipitation anomalies.

Can a big year happen? Sure. Can a mediocre or bad year happen too? Yep.

There’s simply too much chaos in the system and too much that we don’t yet know or understand to be able to accurately predict the season to come. The past does give insights, but the past also occurred in conditions with less total background global warming into the earth system. While we can do our best to model out thousands of scenarios, even using AI, we simply cannot account for all the variables and unknown unknowns lurking in the future.

So where does this leave the Central Sierra? Based off current conditions and what we do know, the Climate Prediction Center places the Tahoe Basin in the swath of “anything’s possible” for the coming season.

I would anticipate anything happening this year, but with a lean in expectations towards warmer than average temperatures and higher snow levels. The earth is warming and with a historical mean snow level of 5000′-6000′ in the Central Sierra, there’s not a lot of grace around lake level when the background conditions are 2-3°F warmer with each storm.

There’s plenty of high terrain in the Sierra. With the right timing, knowledge, creativity, and effort, anyone can have a great season in the backcountry, no matter what the seasonal forecast suggests.

Here’s to another great season!