Tahoe Backcountry Snow

0600 temp. at 6350′ in Carnelian Bay: 34.2 deg. & 94% RH

No backcountry obs. today.

Weather and forecast thoughts:

Today is the last calm day before the next storm system begins impacting the region. Highs will be in the upper 40’s to low 50’s around the lake under a mix of clouds and sun. Tonight’s lows will again be in the low to mid 30’s under cloudy skies. Southerly breezes will start announcing the coming change later today and tonight, steadily gaining strength before maxing out with the storm’s arrival late tomorrow.

Models continue to show a strong AR approaching the coast tomorrow that marches across the state bringing a wallop of heavy precip. and high winds. Winds will peak by late Weds. before falling off behind the initial band of heavy precip. By the time the storm arrives into the Sierra, snow levels will start near 7000′, then crash over the evening on Weds., bringing snow to all backcountry zones in Tahoe. Snow levels should settle in the 5500′-6000′ range by Thurs. as snow continues falling throughout most of the day. The heaviest snowfall rates look to affect our area from the wee hours of Thurs. through Thurs. morning before snow turns more showery in nature on Thurs. afternoon.

By Thurs. night, storm totals above 7000′ could range anywhere from 1-2′ with locally higher amounts along the crest, while Tahoe communities can expect 6-12″.

Fear not, for this looks to be the opening salvo! Moist, unstable flow under a cold airmass will continue to bring snow showers to our area Fri. and Sat. A few inches of refresh each day seems likely.

Sun. through Tues. things get interesting. In the last day, the GFS has consistently shown another low developing off the CA coast that taps into a robust plume of subtropical moisture. In the models, this phases with the colder air to create a solid Sierra dump starting Sun. and lasting into Tues. At this point, this early week storm looks like it could be more potent than the system coming in tomorrow. It’s still 5 days out and details remain fuzzy, but the model trends and atmospheric ingredients are promising for getting a proper Sierra storm.

The dynamics in the atmosphere are highly conducive to winter storms affecting the Sierra over the next week to 10 days. Just for good measure, be sure to wash your car today before humbly tuning your sticks and rechecking avy safety gear. The weather gods have done a great job at neutering the winter this year, but in case they are feeling merciful, it’s never a bad idea to be ready.

0430 temp. at 6350′ in Carnelian Bay: 33.8 deg. & 98% RH

0515 temp. at 8650’ Tamarack TH: 31 deg.

Backcountry obs.:

Crust. Thin crust, thick crust, soon-to-be corn crust, and extra tasty, crispy garlic crust: the backcountry has it all this morning!

I headed out this morning to check on refreezes and see how the snowpack is holding up to prolonged warmth. Early morning snow surfaces in the Tamarack area refroze last night in drainages and on ridgetops. Some mid-slope treed areas were a bit softer from trees reflecting energy back into the snowpack. Colder aspects (NW-NE) host variably supportable crusts making turns difficult and unpredictable: combat skiing. Solar aspects are supportable and firm. I did see signs of baby corn snow growing on S aspects, so if you time it right, you might just be able to steal a spring corn run in January.

The current crust/wet snow situation should continue until the arrival of the next storm system late on Weds. Now that the PWL (persistent weak layer) has largely healed in the snowpack, future instabilities will likely depend on how new snow bonds with the current crusts. The old moniker “today’s surface is tomorrow’s weak layer” will be especially relevant.

Weather and forecast thoughts:

Today will be warm and sunny with light winds and highs in the lower 50’s. Expect another night of mostly clear skies, calm winds and lows in the low-mid 30’s. Some valley fog is also possible at night. Rinse and repeat for Tues. and Tues. night.

Weds. begins the great pattern change with winds and cloud cover on the increase ahead of rain/snow starting late afternoon and into the evening. Rain should transition to snow overnight for all elevations, including lake level. Thurs. will be a storm day with snow continuing before tapering off to snow showers overnight Thurs. and into Fri. with temps remaining cold (20s-low 30’s).

Above 7000′, 12-18″ seems like a plausible estimate for this first storm in the pattern. At first glance, this one also looks like it’ll come in right side up with denser, warmer snow starting off, followed by lighter, colder snow towards the end. Down at lake level expect lesser amounts (6-12″), but enough to transform the landscape back into winter. Finally.

The action might mellow a bit over the coming weekend, but temps will stay cold. Residual flow off the Pacific looks to keep snow showers likely Sat. and Sun. Looking at next week, the overall pattern remains conducive to cold, potent, and potentially convective storms with a robust N. Pacific jet just to our south. This keeps us cold while favoring storm development near the central and southern CA coast.

True to form, another potent low began showing up last night in the GFS models for the beginning to middle of next week. This storm would bring another round of significant snow to the Sierra with cold temps hanging on for the duration of the event.

Winter looks like it’s finally making a comeback starting Weds. and continuing for at least a week. Get your sticks ready!

0630 temp. at 6350′ in Carnelian Bay: 34.9 deg. & 98% RH

No backcountry obs. today

Weather and forecast thoughts:

Warm and dry weather is here as an anomalously strong ridge of high pressure builds over our region the next few days. Highs today through Weds. will reach the 50’s throughout the Tahoe Basin under mostly sunny skies. Lows will be in the mid to lower 30’s each night.

Areas of valley fog in valleys, meadows, and along the immediate Tahoe shoreline can also be expected each morning with inversions. As of this writing, temps. are 5-10 deg. warmer midslope (7000-8000′) again today than they are at lake level. High pressure coupled with weak surface winds is inhibiting any mixing in protected basins, allowing cold air from the snow pack to flow downhill and pool, inhibiting the air near the lake from warming as quickly as upper elevation slopes exposed to relatively stronger flow.

Big changes are still holding in the forecast starting Weds. afternoon as the ridge moves out and a strong Pacific jet extension begins sending storms into the Sierra. The first storm comes in late Weds. night starting warm with snow levels up around 8000′, quickly lowering to below lake level on Thurs. and beyond. The bulk of the energy for the first system will be directed at Tahoe and points south, but even without being in the direct bullseye, our region has solid chances of racking up some appreciable snow amounts: a foot or more.

This will not be a one and done storm. Cold and stormy conditions look likely continuing into next weekend and the first full week of February as the jet stream parks itself over SoCal in a position highly favorable for storms to affect our area.