Tahoe Backcountry Snow

NOTE: Since most of the snowpack melted away in March, I’ve taken a breather from the site to attend to life: family, vacation, and completing my forecasting certification from Penn State. Posts may be more intermittent in the near term, but will likely pick up again later in the spring as my focus shifts from snow to summer mountain weather.

Backcountry obs.:

Lo and behold, despite a few sharks emerging from the depleted base, backcountry season holds on in the Mt. Rose area, with plenty of help from the recent multi-foot storm from 4/11-4/13. Touring from 8650′ to 9950′ at dawn on 4/15, revealed a transitional spring snowpack with everything from crust to powder. Below 9300′, differing varieties of sun crusts from supportable, soon-to-be corn, to breakable but nearly-unturnable death crust, covered all aspects. Higher up, winter snow and fluffy powder greeted this curious skier dropping into a north facing bowl at sunrise. Smiles quickly followed. However, once at lower elevations, navigating breakable crust made returning to the car without injury a more tenuous pursuit.

Worth noting is that despite the recent cold temps and cloud cover, the high April sun quickly transitions new snow from cold fluff, into baked mashed potatoes, to melt-freeze crusts on all but the most northerly aspects within a day or so. As long as there are refreezes, solar aspects transition to corn within a few days. As more snow falls in the next few weeks, expect conditions to change quickly. Timing will remain crucial to finding desired conditions.

Weather and forecast thoughts:

Things are moving again. The “stuck” pattern of persistent high pressure in the west and a trough in the east, so common this past winter, has been replaced by a transient and progressive parade of storms impacting the Sierra. For the latter half of April, ensembles agree on a mix of deep wandering low pressure systems and transient high pressure bringing fickle spring weather: periods of snow, rain, and wind interspersed with cool and sunny days. Even though the tide of the snowpack is in its inevitable retreat, occasional systems will likely add periodic refreshes over the High Sierra, slowing the outgoing tide.

The 500mb anomaly analysis today through late next work week (4/16-4/23) helps illustrate the progressive pattern.

Today’s (4/16) cool, breezy weather associated with a departing trough in the Great Basin, gives way to a ridge of high pressure Fri – Sun (4/17-4/19) bringing mostly clear skies, moderating temperatures, and light winds for the first half of the coming weekend.

Expect highs in the backcountry above 8000′ to climb into the low 40s on Fri and mid 40s on Sat (4/17-4/18) under sunny skies with generally light winds. Breezes out of the N and NE on Fri will become variable Sat before transitioning back to the S and SW on Sun (4/19) ahead of the next weather system.

Lows on Fri and Sat nights will drop well below freezing, with some inversions developing both nights, keeping depressions and valleys a few degrees cooler than midslope areas. The combination of ample sun, light winds, above freezing days and cold nights will provide a great window for excellent spring corn skiing.

Sun (4/19) increasing SW winds and clouds will signal the arrival of the next storm system which will linger across the west for most of the coming week. Models suggest a fairly deep cutoff low pressure system dropping in from the Gulf of Alaska and meandering about off the CA coast before coming ashore midweek.

Lifting dynamics with this cutoff low look substantial. Coupled the seasonal instability common in spring, this system could also instigate afternoon convection and thunder along the Sierra.

Models also suggest the system will phase with Pacific moisture, creating good chances for rain and snow in the backcountry. Below is the ECMWF forecast total precipitable water (PWAT) anomaly analysis for the same period. (PWAT anomaly shows how much more water than climatologically normal will be in the entire atmospheric column, able to be rained or snowed out.)

Because both the dynamics and moisture look to phase, expect unsettled weather with accumulating rain and snow across the backcountry.

Snow levels will likely fluctuate with the system dropping to near lake level at night starting Mon night (4/20), then rising again each afternoon with the heat of the day.

Because the low is dropping in from the cool Gulf of Alaska, it will bring colder air and lower snow levels to the Sierra. However, should it stall out over the warmer than average waters off the CA coast, snow levels would edge higher as the warmth of the ocean moderates air aloft.

This far out, there is some model disagreement, along with the lower than normal skill models tend to have in April. Expect changes to the forecast as the week draws closer. A big dump looks unlikely, but unsettled days of rain and snow showers–and even some thunderstorms–look possible.

Until then, a brief window of cool sunny days and cold nights will bring great corn conditions across the higher terrain. Deep in the mountains, backcountry season hangs on.

Backcountry obs.:

Over the past week, I observed the snow in the Mt. Rose area primarily on foot, running newly uncovered trails all the way up to and just above snowline. As of Fri (3/27), usable snow doesn’t begin until around 8500′, just below Tahoe Meadows. As expected, snow surfaces are heavily textured with pocked, pre sun-cupped divots and forest debris, more reminiscent of late spring and early summer.

The highest Tahoe trailheads above 8500′ still have snow, but patches of dry ground grow larger each day. Tree wells now expose bare ground and solar aspects are dry, even up to summits, limiting skiable terrain to N-E aspects in what will soon become summer patch skiing.

Where snow remains, there is still fun to be had. Refreezes above 8000′ returned this week, with increased winds and cooler temps aiding radiational cooling to firm up snow surfaces overnight. Touring from 8650′ to 9300′ at dawn on 3/27, I found supportable, refrozen crusts making travel quick and at times slippy. Below 9000′ in heavily forested areas, snow surfaces hadn’t refrozen as completely, yet were still supportable, while open areas had frozen hard. With temps climbing into the mid 40s each day, mid morning snow surfaces should soften into corn or summer schmoo, making for buttery-fun last turns.

It’s been a fun, yet short ride this season, Señor Snowpack. Thanks for your efforts, but please do better next year. You came late, doddled for a bit, then peaked with a flash, before quickly disappearing out the back door. You’re always invited, but next time, make yourself comfortable and hang out for a while.

Weather and forecast thoughts:

Today and tomorrow mark the end to three weeks of anomalous heat as more seasonal temperatures and showery weather return for the coming work week. Today (3/29) high temps above 7000′ will make one last return to the low-mid 60s under sunny skies, while lows tonight fall into the mid to upper 30s. Light to moderate zephyr-like winds will pick up out of the S and SW this afternoon.

Monday (3/30), increasing cloudiness and cooling temps will kick off the week presaging the arrival of a more unsettled, showery spring pattern as the dominant ridge of high pressure responsible for weeks of warmth, finally decamps. Highs will reach the low to mid 50s on Monday under a mix of clouds and sun, eventually becoming overcast. Clouds build in Mon night and by Tues (3/31) rain and high elevation snow showers look likely, lasting into late Thurs (4/2). Lows Mon night should fall into the mid 30s above 7000′.

As the ridge of high pressure moves off, a trough of low pressure will drop down from the Gulf of Alaska, with its parent low likely coming ashore near Columbia River late in the work week.

While the pattern will turn cooler and showery with snow levels falling to near lake level by midweek, this system doesn’t appear to have the dynamics and moisture to put down any significant snowfall that could hold or reverse the fortunes of the backcountry.

Upper level dynamics through the period (Tues-Fri) show weak shortwaves passing through the Sierra on Tues and Weds (3/31 and 4/1), followed by the main low coming ashore in the PacNW on Thurs (4/2). In both cases, the main lifting dynamics look weak to moderate over the Sierra, lacking the driver for any long lasting, heavy precip.

Available moisture for the above dynamics to interact and precipitate out doesn’t look very impressive either. While there will be enough to create generally spring-like rain and snow showers, models don’t currently depict any deep moisture feeds that align with the strongest dynamics, a recipe for more prolonged, heavy precip.

Model ensembles for total precip. through Fri evening (4/3) follow the same script. Modest amounts likely fall throughout the week, renewing soil moisture and keeping lower elevation trails wet and tacky, while putting down a few inches of snow for the upper elevations.

But a few inches of snow atop dirt won’t do it. Some of the highest zones above 8000′-9000′ might see up to 6″ of new snow through Fri, which could make for a few fun, end of season powder turns for the most motivated.

Looking into next weekend, skies clear out and temps look to rebound to above normal as another ridge of high pressure likely rebuilds in the Eastern Pacific.

Winter’s probably gone, but the glories of trail season await!

Backcountry obs.:

Rather than fight the weather, I’ve put away the ski gear for the time being and gotten my backcountry jollies on foot, sampling the newly available trail running opportunities through the ever expanding snow-free zones. As of 3/23, continuous, tacky, open trail exists almost uninterrupted below 7500′ on all aspects, and below 8000′ on all but protected NW-N-E aspects along the NE corner of the Tahoe Basin from the Mt. Rose backcountry to Tunnel Creek.

Snowpack starts abruptly around 8000′ on most treed aspects, but is absent on windward and solar faces all the way up to ridgelines and summits. Where snowpack does still exist, surface snow is more reminiscent of late spring/early summer, pocked and littered with forest debris and rotten from multiple nights of poor to nonexistent refreezes. In the trees, pronounced, rolling undulations are growing ever more-prominent as tree wells melt down to the ground, leaving the remnant fins and waves of deeper snowpack in between. Tree skiing is becoming necessary survival/transit skiing after better turns up high.

Above treeline and 8000′, open N and NE facing terrain is in better shape. Despite lows only bottoming out in the 40s, dry air and radiational cooling have promoted marginal surface refreezes on the majority of nights over the past week, creating supportable snow early each morning. By late morning, temps warming into the 50s under direct or slightly-filtered sunshine has overcooked corn into wet mush on most days. But with the right timing and right objective, fun spring skiing is still out there over higher terrain. The snowpack might be hammered and waning, but it’s still hanging on up high.

It’s spring and the backcountry’s primed for multi-sport days. What’s not to love about biking, running, climbing, and paddling in the same day or skiing a line and mountain biking home?

Weather and forecast thoughts:

Anomalously warm and dry — yet less record shattering — weather will continue through the week and coming weekend (3/25-3/29). Highs above 8000′ on the remaining snowpack will climb into the mid-upper 50s each day with lows in the upper 30s to low 40s in a relatively dry airmass. Expect surface snow in forests to refreeze poorly most nights, especially with any cloud cover, while open areas with a clear line of sight to the sky will cool and resolidify more efficiently each night.

Winter 2026 has been the warmest on record and the past ten days blew away any previous March records by wide margins. Equally notable is that rather than occurring over a day or two, this heatwave has persisted for well over a week–and will continue for another–with multiple waves of extreme warmth. While heat has felt like the norm this season and many folks have already switched their minds to summer activities, it’s worth taking note of the scale of the recent event. It’s truly historic.

On Mon (3/23) NWS Reno put together a graphic summarizing the situation:

The main culprit is the historically strong and resilient ridge of high pressure over the west, directing any and all weather north into Canada. Locations under the ridge bake as high pressure pushes air downward, drying it out and warming it up via subsidence.

This morning (3/24), the ridge remains locked in place, as noted by IR satellite imagery showing clear skies across CA and the jet stream shunting any moisture northward toward into BC and WA.

As a result, while not summer-warm, the next week will continue to be 10-15 degree above average as noted by ground level temperature anomalies for the coming week.

But as has happened both in December and after a bone-dry January earlier this season, eventually the pattern breaks. Models over the past few days have started to agree on a pattern shift pushing the ridge eastward and allowing a trough of low pressure to swing in its place. Cooler and wetter conditions look more likely to return by the beginning to middle of next week.

The exact details of the shift will become clearer in the coming days. For now, expect an end to late spring warmth and the return of cooler temps, and the chance of rain and higher elevation snows starting around the beginning of April.