Tahoe Backcountry Snow

Looking up in the near term

December 13th, 2024
0415 temp. at 6350′ in Carnelian Bay: 28.9 deg w/ 97% RH / 3″ new snow

0515 temp. at 8650′ Tamarack Peak TH: 20 deg / 3-6″ new snow

Backcountry obs:

The wait for a refresh is officially over. The storm that impacted the area over the past 36 hours has moved out, leaving anywhere from 3-6″ on the Mt. Rose backcountry. All old, crusty tracks are gone and a new snow surface has returned for your sliding enjoyment.

Moderate SW winds blew through the zone this morning, moving snow around on at all elevations, even lower on the mountain. This wind transport has made estimating total new snowfall a bit challenging: some areas favoring wind deposition have 6-10″ of fresh, while other more sheltered zones only have a few new inches.

While not bottomless, the new snow is a welcome change, skiing playfully fast and fluffy, with only light scrapage on the refrozen old snow below. Snow density is just enough to be supportable through most turns, preventing caught edges on old frozen tracks. It’s still low tide: rock skis recommended.

Weather and forecast thoughts:

While modest by Sierra standards, the recent storm (12/11-13) did help improve snowpack conditions around Tahoe, if only by cleaning up the surface. Areas along the crest received up to 12″ while backcountry zones in the Rose area picked up about half that amount. The next – and more significant – wave in the storm series is posed to begin impacting the area late Fri night (12/13) peaking by Sat afternoon (12/14), before tapering off Sat night.

This morning, rain and snow showers are already impacting Northern California, and looking further afield into the Pacific, more is on the way. Cloudy skies will prevail today (12/13) with on and off snow showers and peeks of sunshine, with snow becoming steadier in the evening after nightfall. Highs today should top out in the mid 30s around town with upper 20s in backcountry zones, cooling only slightly overnight tonight. SW winds will pick up during the day and overnight tonight, becoming strong especially over higher terrain and ridges.

The main event begins in earnest on Sat (12/14) as heavy snow moves into the area in the morning, increasing throughout the day, before winding down tomorrow evening. Highs tomorrow will be in the mid 30s around the lake, while above 7000′ temps will remain below freezing, likely only flirting with the 30 deg. mark. Tomorrow night temps will plummet to the teens around 6000′ to low teens and upper single digits for backcountry zones above 7000-8000′.

Snow levels for this next storm will start around 5500-6000′ and could rise to or slightly above lake level (6250′) late tonight or early tomorrow morning (12/14), before falling again late tomorrow with the passage of a cold front. This warm start and cold finish will likely produce a denser initial few inches, followed by increasingly cold and fluffy snow towards storm’s end.

By Sunday morning, up to 18-24″ of new snow with locally higher amounts is very possible for areas along the Sierra crest and west side of the Tahoe Basin. Backcountry zones on the E side of Tahoe will likely receive a fat foot, or more with some luck. Snow totals for Tahoe communities are a little more uncertain due to the possibility of snow levels climbing above 6500′. Expect anywhere from 4-10″+ with the highest amounts along highway 89, lowest values on the east shore. Storm totals could be a bit higher should colder air prevail throughout the entire storm, or considerably lower if warmer air on the front side of the system hangs on longer than expected.

Sunday will be mostly sunny and chilly with highs in the mid 30s around the lake, 20s in the backcountry. A light snow shower or two can’t be ruled out in the mountains, especially in the afternoon, but with minimal additional accumulations.

Cool conditions prevail on Monday as another weaker storm skirts the area to the north. Models show snowfall impacting Tahoe from late morning through the evening, perhaps delivering another modest refresh to the mountains.

Looking at the rest of next week, the storm door appears to close yet again as dry weather and milder temps return for a bit. Enjoy the new snow while it’s here!
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Modest improvement on the way

December 11th, 2024
0400 temp. at 6350′ in Carnelian Bay: 31.4 deg. w/ 52% RH

0500 temp. at 8650′ Tamarack TH: 30 deg.

Backcounty Obs.:

I got out this morning on a quick tour to check the state of the Rose backcountry snowpack after a few weeks of mild, dry weather. Overall, the snowpack continues to hold its coverage and ski-ability above 8500′. Snow in the area is heavily tracked and worn. Most surfaces that receive any appreciable sunlight are coated in a supportable, combat crust. Cold, sheltered areas below treeline a mix of thin crusts and soft, cold, recycled pow, aka. facets. While soft snow exists, fresh tracks are rare.

Near and above treeline, recent N and NE winds have created some variable, cold windboard on and near ridges high in N-E facing terrain. Further down slope, the snow surface returns to soft, cold recycled pow. Digging handpits and probing these areas show that the snowpack now consists largely of faceted snow with little cohesion. It skis nicely now, but could become problematic once covered in higher density new snow.

Of note the past few days has been the dryness of the airmass. Dew points this morning on Slide Mountain were in the -20 deg range, translating to single digit RH levels. Yesterday and Mon. (12/9) were similar. This dry air is sublimating moisture out of the snowpack and cooling snow grains as it does so. This creates the poorly bonding recycled pow that’s fun to ski now, but will likely create avalanche problems in the near future.

Weather and forecast thoughts:

The storm door is finally reopening after weeks of patiently waiting as a modest storm begins impacting the Tahoe area late tonight (12/11). Snow should begin falling after midnight and will continue into most of tomorrow for all backcountry areas – and even in town around the lake. Local communities should pick up 2-5″ by Fri AM, with greater amounts N and W. Backcountry zones above 7000′ have a decent shot of receiving 4-8″ of refresh on the currently haggard, backcountry.

Temps. will remain cool throughout the event with highs tomorrow (12/12) wobbling around the lower to mid 30s in town, with 20s in the mountains. Snow levels look to remain below lake level for the entire storm.

Cool conditions and snow showers with little additional accumulation will linger about on Fri before the next storm moves into the area late Fri night into Sat.

Models are in fairly consistent agreement that the weekend storm should begin early Sat morning and increase in intensity throughout the day. Snow levels will begin near or above lake level (6500-7000′) on Fri night / early Sat, and fall throughout the day on Sat as cold air moves in on the back side of the system. Scattered showers with lighter accumulations will finish out the storm Sat PM and Sun.

As is typical, the highest snow totals will be west and north around the Tahoe Basin, favoring the crest. Backcountry areas have decent odds of picking up 12-14″ of new snow, while communities around 6000′ will likely see only a few slushy inches. Warmer temps and a more robust moisture tap will produce higher density snow, slightly moderating the low tide backcountry conditions, albeit atop a base of cold, loose facets. The adage, “today’s snow surface is tomorrow’s weak layer”, could prove particularly insightful in the coming days.

Looking ahead to next week, another cold, modest storm could be in the cards for the Mon-Tues time frame bringing another few inches of refresh for all elevations.

Weeks of patience might just be about to pay off.
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Thick or thin crust?

December 5th, 2024
0430 temp. at 6350′ in Carnelian Bay: 30.8 deg w/98% RH

0500 temp. at 8650′ Tamarack Peak TH: 22 deg.

Backcountry obs:

How do you like your crust: thick or thin? Crust is largely the only surface on offer in the Rose area backcountry as of this morning (12/5). The multitude of refrozen tracks, pine litter, and the occasional frozen dog turd really have the area looking haggard. Coverage is holding on, but some thin, wind-exposed zones near tree line are beginning to burn out down to bare rock and scree.

Near and above treeline, N-NE aspects hold cold, dry snow. Hanging depressions and sheltered areas in the trees did host widespread surface hoar atop 2-3′ of soft, old snow. Digging handpits in this area doesn’t reveal clear density changes in the snowpack, rather a fairly consistent pack of dry, degrading snow grains that adhere poorly, if at all to one another. Look out for these potential stability issues for the next snow event.

While it’s always nice to get out on a predawn tour, navigating crust and thin coverage made skiing tenuous at best, to full on combat in some zones. Not recommended for pleasure unless masochistic training is your thing.

Weather and forecast thoughts:

One thing’s for sure: the best turns of the season are yet to come. The stagnant, dry pattern locked in over Tahoe looks to continue with some minor changes over at least the next week. By mid-month, models hint at storms returning to area. The flavor and intensity of these future systems remains unclear as models change with each successive run. What does look promising, however, is a consistent signal in ensemble forecasts for change in the overall pattern favoring more active weather.

For the near term, expect mostly clear skies with highs in the 40s and lows in the 20s in valleys and depressions, near freezing temps along mid-slope areas, peaks and ridgelines: classic inversion weather.

A system will arrive into the PacNW Sat/Sun, then dive south and east into the Great Basin and western slope of the Rockies for early next week. Tahoe will see nothing more than cooler temps and increased NW winds late this weekend into early next week. This might help clear out the stagnant, smoky air plaguing area valleys.

Ridging and high pressure return for the middle/end of next week (12/10-12/13) with sunny skies, cool days and cold nights, much like this week.

Models and their ensembles do show changes to the pattern starting next weekend (12/14-12/15) with the ridge breaking down and storms potentially returning to the area.

Winter is bound to return, it’s just a question of when.
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Looking up in the near term

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Modest improvement on the way

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Thick or thin crust?

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