Tahoe Backcountry Snow

0700 temp. at 6350′ in Carnelian Bay: 27.3 deg. & 98% RH

9″ new snow

No backcountry obs.

Weather and forecast thoughts:

The much anticipated storm is here. This morning dawned with heavy snow and mainly light winds. The forecast is still holding for 1-2′ in Tahoe communities with 2-3′ above 7000′ through tonight. Heavy snow will transition to more showery, intermittent snowfall this afternoon and evening continuing into tomorrow, but with lesser amounts. The most intense accumulation will be this morning through afternoon.

One notable change to the storm forecast is the possibility for snow levels to climb near 6000′ late this afternoon into the evening. The subtropical fetch of moisture coupled with anomalously warm sea surface temps in the eastern Pacific near the CA coast may add enough heat to the storm to, yet again this season, raise snow levels. Rain may mix in at the lake, especially when snowfall rates ease. Snow levels drop again late this evening. The risk of rain mixing in from 7000′ up is low.

However, the storm profile of a cold start and warmer finish at all elevations raises the prospect for instabilities within the new snowpack. Denser snow falling this afternoon as warmer air comes into the storm could overload lighter, drier snow near from earlier that rests atop old, hard crusts. If heading out into the backcountry today or tomorrow, keep a lookout for potential density changes in the new snow.

Colder air filters back in tonight as snowfall rates diminish, but maintain throughout tomorrow. For now, it’s time to sit back and enjoy the storm. Great skiing awaits…

0700 temp. at 6350’ in Carnelian Bay: 15.8 deg. & 92% RH

3.75” new snow.

1000 temp. at 8650′ Tamarack TH: 17 deg.

Backcountry obs:

The backcountry is back in prime shape today. 6-8″ of cold, right side up snow rests above the old crusts. From mid morning through early afternoon, a mix of sunshine and clouds rolled over the mountains with barely a breath of wind. By 1pm, light flurries had turned into bursts of graupel and snow, limiting visibility during peak snowfall periods. Very little, if any, wind affect was noted on the snow surface.

The skiing is superb. Enough new snow has fallen recently to erase nearly all evidence of previous crusts. Skin tracks hold on traversing slopes and turns are soft, fast and oh so fun.

Other than small sluffs in steeper terrain, no instabilities were noted. The current cold surface snow may become a weak layer if the new snow coming in this evening is of greater density. That said, the dynamic nature of the coming storm will likely produce snow of varying densities throughout the event promoting storm slab development. Heads up if heading out for storm skiing tomorrow.

Weather and forecast thoughts:

Convective showers dropped a few inches of cold snow last afternoon and evening at lake level. Today dawned with partly cloudy skies and some heavy looking low level clouds. The atmosphere feels primed for a stahwm!

Today is the last day of calm weather before the storm moves in tonight. Highs today will be struggle to get to freezing around the lake, with teens and twenties in the backcountry. A mix of clouds and sun, trending more towards clouds as the day progresses will keep any fresh snow soft and delightful for backcountry revelers. A few stray snow showers or can’t be ruled out for the rest of the afternoon, but the main action won’t get going until well after dark tonight.

Models today continue to trend upward in snow totals with NWS Reno showing (80-90% chance of 3′ at pass level and 90% chance of 1.5-2′ at lake level. Timing of the heaviest snowfall has also come forward with heavy snow starting tonight during the wee hours and continuing through tomorrow before snowfall rates ease a bit for Sun. evening. Snow will continue falling through Mon. and into Mon. night.

A more showery regime sets up for Tues. before another quicker and weaker storm could impact the area on Weds.-Thurs. Temps for the next week will remain cold with highs barely reaching freezing at lake level through the end of the week. Needless to say, that means snow continues to pile up for all backcountry zones at all elevations. Hopefully some lower elevations zones will finally come into play.

Looking beyond this week, models show the storm door remaining open, so additional storms may line up. The snow gravy train is rolling in. Get it!

0430 temp. at 6350′ in Carnelian Bay: 29.3 deg. & 89% RH

Trace new snow

0515 temp. at 8650′ Tamarack TH: 20 deg. under flurries/light snow

4-6″ 36hr. storm total

Backcountry obs.

Overcast skies with light snow started off the morning at lake level and in the backcountry. The 2/1-2/2 storm underperformed with snow totals, but there’s enough of a refresh in the backcountry to make skiing more fun than a frog in a glass of milk!

Light to moderate SW-W winds raked the forests and ridgelines at dawn giving a subtle surface texture to the cold and light new snow. Despite its levity, the new snow still has enough texture to provide cushion and float above the old crust layer. Skinning in steep, traversing terrain provides some challenges: the poorly bonded new snow slides out on the firm crust beneath.

In wind-exposed areas, firm surfaces are forming as windward faces rime in the low clouds and high humidity. Lee zones do have growing drifts with the potential for wind slabs to enlarge modestly as more snow and wind arrive today. No instabilities like cracking, whumphing, or hollowness were noted, but skiing initiated some minor sluffing on steeper terrain.

The wind-kissed, cold pow is just enough to provide consistently soft turns. Turn too sharply and the crust becomes evident, but not problematic. The fun is back!

Weather and forecast thoughts:

Today will be mostly cloudy with some peeks of sunshine in between snow showers. Highs around the lake will stay in the low 30’s with temps in the mountains hanging in the low to mid 20’s. A few inches of accumulation are possible in town while up to 6″ could fall in the mountains, potentially more along the crest and west of CA 89.

Showers will increase in intensity this afternoon as another impulse of energy moves in off the Pacific and aligns with afternoon heating. The combination of lifting from the impulse, with added instability from daytime heating could fire off some heavier, convective showers with short-lived intense snowfall rates.

Tonight through Sat. and Sat. night snow backs off again to just some lingering showers. Temps. remain cold with highs in the low 30’s to 20’s depending on elevation, with low’s into the teens and 20’s.

Sunday the big show gets going. The much advertised “biggest storm of the season” looks to take shape and dump its heavy load on the Sierra from Sun. daybreak through early Tues. An impactful storm is likely with the ability to close roads and create a snowpack at all elevations in the Tahoe Basin. Just how much is still in flux.

As of this morning, models show a strong low combining cold air, dynamic lift, and a robust tap of subtropical moisture moving into the area on Sunday, dumping the heaviest snow Sun. through Mon. AM. An intense plume of moisture looks to arrive from the south and shuffle north during the morning on Sunday. The flow within the fire hose – from the SW – will align well with the topography of the Sierra to create enhanced lift and heavy snow. Highest amounts will be along the crest, but the system will also create efficient spillover into NV and points east.

Today’s model runs trimmed snowfall amounts back a bit for Tahoe and bumped them up for the Eastside to our south, as the plume will likely originate over the Central/Southern Sierra, move north, hang out, then begin moving back to the south before breaking apart into more intermittent snow. Probabilistic models show a 50-60% of 12″+ for Tahoe communities, with 60-80% of 2-3’+ along the Sierra crest. Totals jump up to 4’+ for the crest in Mono County, with 2’+ likely for Mammoth and June Lakes.

Each storm is unique and this one could meet those marks or even overperform. However, considering the trend of models overpromising this season, these amounts may be trimmed back in future forecasts or during the actual event. Time and the atmosphere will tell.

Moving beyond Monday, the active, cold pattern continues with showery, intermittent snow Tues. and Weds., potentially picking up again with another storm arriving from the NW around Thurs. Keep it coming…

Hey winter, it’s good to see you.