Tahoe Backcountry Snow

Another snowfall surprise and a warmup

December 17th, 2024
0400 temp. at 6350′ in Carnelian Bay: 30.1 deg.

New 24 hr. snow: 5.5″

0515 temp. at 8650′ Tamarack TH: 28 deg.

New 24 hr. snow: 6-8″

Backcountry obs:

Yesterday’s storm surprised yet again with higher snow totals around the northern side of the lake, while points south picked up a slushy inch. Warm, moist air moved into with the system around mid-morning bringing snow levels up to around 8000′ by afternoon, even in spots that initially picked up more snow than expected. By noon, moderate rain soaked backcountry zones around Mt. Tallac, Emerald Bay, and the West Shore. This morning, rain crust reports abounded in much of the backcountry below 8000′.

The one zone that survived the warmth: Mt. Rose. Temps during the storm never crested freezing, resulting in another 6-8″ of thick cement, resetting the snow surface and providing fun, thick hero pow.

The combination of high water content snow and strong winds during the storm has created abundant wind board along ridgelines and in exposed areas. While not escaping the wind entirely, W-N-E aspects skied well at dawn on wind affected, thick buff, turning to lightly textured thick pow in the trees. Add a little extra pop to each turn for best results.

Weather and forecast thoughts:

Calm weather and warm temps will dominate the rest of the workweek both around town and in the backcountry. Expect morning fog and inversions in valleys and depressions with lows around freezing, or just below.

Daytime highs will hit the low 50s around the lake Weds – Fri, while backcountry areas reach the upper 30s above 8000′, to 40s below 8000′. Summits and ridgetops may not drop below freezing at night, but lower dew points and RH may preserve whatever cold snow that didn’t get soaked through evaporative cooling.

A stormy, active pattern is in the cards for the weekend, then continuing into Christmas week. The first storm takes aim on Tahoe for Sat and Sun (12/21 – 12/22). This one looks to have a warm, atmospheric river component, possibly driving snow levels all the way up to 9000′ and soaking the snowpack for all areas. Luckily the past few storms have laid down feet of thick cement that should handle a short-lived period of rain and warmth.

After a break in the action late Sun – Mon, models are in fair agreement that another storm will roll in for Christmas Eve / Christmas Day, this time bringing the gift of colder air and lower snow levels. Hopefully the fluffy fun returns just in time for the holiday.
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‘Twas a good storm; now some warmth

December 16th, 2024
0530 temp. at 6350′ in Carnelian Bay: 33.3 deg. w/90% RH

New snow in past 24 hrs: trace

12/13-12/14 total snowfall at 6350′ in Carnelian Bay: 17″

Backcountry obs:

The Fri / Sat (12/13-14) storm really over delivered dropping nearly a foot and a half on the north shore and up to 2-3′ for areas along the crest. Snow fell consistently throughout the event, with hours-long periods of heavy snowfall. Strong winds accompanied the storm, creating wind sculpted surfaces, even in sheltered zones below treeline.

Rain never came to lake level on Sat as temps hovered at or just below freezing through the warmest part of the storm. This translated to far higher snow totals than expected. And while the storm remained cold, the snow that fell was heavy, dense Sierra cement that the high winds distributed around nooks and crannies. Coverage has vastly improved down to 7000′, putting zones previously too bony to open up and lay into turns, now into play.

Touring in the Rose zone on 12/15 revealed at least 2′ of new, wind-affected snow with a few density changes throughout the new snow column. By dawn, winds had slackened and shifted to the NW, creating some turnable, yet fun wind buff near ridgetops and on open bowls. On E aspects, a few reactive wind slabs failed with ski cuts, yet did not extend beyond a few feet off the ridgeline. Interestingly enough, I didn’t observe any natural avalanches from the storm, despite the windspread faceted snow from late last week. Have the weaknesses healed or does the white dragon lurk below? Time will tell.

Weather and forecast thoughts:

Today (12/16) a quick, weak storm will swing through Tahoe during the daylight hours, starting as snow for most areas and finishing with a rain/snow mix around the lake. Snow levels should climb to around 7000′ before precip moves out in the early evening. Expect a dense 2-6″ above 7000′ with negligible slush to liquid amounts around the lake. Highs will be in the upper 30s, with lower 30s in the backcountry. Tonight will bring lows in the 20s on the mountains and temps near or just below freezing around 6000′.

Milder air and calm conditions return for the rest of the week with mainly sunny skies and highs in the mid-upper 40s, lows in the lower 30s around the lake. Inversions may develop again at night bringing low clouds and freezing fog to valleys and depressions. This regime will be mild for the backcountry as well with highs above freezing and lows just at or below freezing. The drier airmass and weak Dec. sun will likely keep snow surfaces soft and frozen on cooler, shady aspects.

Models indicate the return to an active pattern starting next weekend with a warm system possibly affecting Tahoe on Saturday and maybe something a bit colder and more robust around Christmas.
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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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Another snowfall surprise and a warmup

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‘Twas a good storm; now some warmth

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Looking up in the near term

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