Tahoe Backcountry Snow

0430 temp. at 6350′ in Carnelian Bay: 30.9 deg. and falling w/ 98% RH

10″ new 24hr. snow. (19″ storm total so far)

0515 temp. at 8400′ Incline Peak TH: 24 deg.

18-30″+ new snow between TH and 9500′ summit

Backcountry obs.

Travel was slow going this morning in the backcountry. Strong S-SW winds and bands of intense snowfall greeted the day reducing visibility and making travel disorienting. Breaking trail up Incline Peak was deep and arduous, made more so by a noticeably upside down snowpack. The lack of any rain crusts and cold, soft snow suggest that yesterday’s warming temps did not crest freezing in this zone. The warm up is clearly evident in a “trap door” snow pack that is noticeably more dense on top than underneath.

New snow amounts increased with elevation and protected areas below treeline held soft snow without much wind effect. The denser snow is about 1-3″ thick at the top of the snowpack, with feet of colder, lighter snow beneath. At and above treeline, ridges have firm cornices and wind pillows that don’t extend very far downhill.

Surprisingly, ski cuts and stomps did not release any wind slabs. Cracking, whumphing, and other obvious signs of instability were not observed. The amount of new snow and its upside down nature were strong enough warnings to avoid avalanche terrain and stick to more mellow, protected areas.

The skiing this morning was great fun, but strenuous. The depth and density of the new snow, coupled with the need to stay off steep terrain discouraged any turning beyond wide steering at speed. Float is the name of the game until the new snow consolidates. If you own pontoons, today would be a day to use ’em.

Weather and forecast thoughts:

The rare low pressure system responsible for yesterday’s storm produced a wide variety of impacts around Tahoe. Snow started before dawn on Sun. with cold temps that inched upward throughout the day. At 8am I recorded 9″ of cold, light new snow at 6350′. By 1pm, temps had just barely edged above freezing and 9 more inches of snow had fallen. Around that time, snow began to taper to showers and temps slowly climbed. By 5 pm, winds increased dramatically and temps continued rising, but more rapidly. By 9pm temps had climbed to 37.6 deg., the high temp. for the day. By this morning, freezing temps. returned along with bursts of heavy snow.

This storm has been yet another reminder of how different and unpredictable each storm can be. Despite all the advanced modeling now available, we never really can know what the future will bring until it’s upon us, especially in an area as varied and dynamic as the Sierra. Slight adjustments in track, ocean water temps, or some distant atmospheric variation can greatly impact how storms interact with the Sierra’s topography, and how much snow falls – or doesn’t – from one area to the next.

Today snow will continue to fall in intense bands throughout the morning and into the afternoon and evening. Temps. will be a bit cooler, keeping snow levels down to lake level throughout the day. Peak temps. will happen around or just after midday, before falling off as the sun’s angle wanes. Tonight a few snow showers are still expected with colder night time temps.

New accumulation today will be highly variable depending on where intense snow bands set up. Some areas in the backcountry, especially along the crest and in the higher terrain, could see an additional foot. Mountain communities should see between 1-6″.

Tomorrow cold temps and snow showers will continue with highs in the low-mid 30’s in town and lows in the 20’s.

Chances of snow showers and cold temps stick around through the work week before calmer weather settles in for next weekend. No big warm ups are on the horizon with high temps in the low to mid 30’s and lows in the 20’s. Backcountry areas will see temps in the 20’s and teens. A moderate warming trend may arrive with calmer weather this weekend.

The snow might be weird, but it’s here. Time to get it.

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!