Tahoe Backcountry Snow

0430 temp. at 6350′ in Carnelian Bay: 31.8 deg & 91% RH

0520 temp. at 8650′ Tamarack TH: 26 deg.

Recent backcountry obs.: Tamarack Peak / June Lake

Spring is here. While the weather continues to be dynamic, the snowpack in the backcountry has settled into the predictable rhythm of melt/freeze with some days not freezing at all.

Recent obs. from the Tamarack zone on 4/22 and 4/25 showed a marginal to solid refreezes on 4/22 and 4/25 respectively, likely softening by mid morning. The area is heavily tracked out and sun cups are beginning to pock the surface of the most sun-exposed and open areas.

This past weekend on 4/20, conditions in the June Lake area were similar with lower elevations marginally refreezing at night, whereas the alpine received more solid refreezes on supportable transitional snow. Descending from around 11,000′ at 9am, upper elevation turns were still firm and fast, while below 9000′ snow had already turned to heavy mank and non-supportable crusts: combat skiing.

Across Tahoe and the Eastern Sierra, temps have not yet fallen into a prolonged period of clear cold nights and warm sunny days that create widespread, quality corn snow. Melt/freeze cycles have happened, but they’ve been short lived and followed by warm periods without refreezes, that have initiated widespread wet avalanche cycles. On the opposite end, this season has also seen a few strings of melt/freeze weather followed by weak winter-like storms that brought a return of snow and unsettled weather with cold temps. It’s been a mixed bag of ying and yang, not quite hitting the ideal middle ground that produces the best spring skiing.

Spring weather thoughts:

Over the past few weeks, a noticeable shift in the storm track and temps has really signaled the seasonal change and arrival of spring. Big, snow producing storms are all but over. Storms from here out tend to not have the same punch and dynamics as the winter jet stream weakens and lifts northward. Systems that do arrive will bring lighter amounts of rain and snow, often in showery and convective form. Periods of colder temps, breezy conditions, and afternoon showers and storms may pass through the region from time to time before eventually fading out into the dry, placid warmth of summer.

With the seasonal weather shift, the desire to be on the snow has begun its rapid wane. Daydreams of running fragrant trails lined with wildflowers and climbing high alpine granite in the summer sun have replaced the urge to venture out in the predawn cold to devour fluffy powder laps. It’s been a great season monitoring the snow and weather and I look forward to starting this back up in the fall. Until then, enjoy the sun and warmth.

0600 temp. at 6350′ in Carnelian Bay: 29.8 deg. & 93% RH

Trace new snow

Backcountry obs.:

I headed out to the Eastside on Sat. and Sun., April 13-14 and skied in the McGee Creek and Pine Creek drainages. Snow is transitioning to a spring-like corn snow in the mid to upper elevations, but as of this weekend, it had not fully formed and is still in a transitional state from 8000′-10000′. Above 10,000′, snow is still cold and wintry on N-NE aspects, especially in steep and protected bowls and couloirs.

The week of April 8-12 brought high temps in the 50s and 60s and mostly clear skies to much of the eastern Sierra, quickly warming the cold snowpack. Initially cold nights with solid refreezes followed the warm days, but towards the end of the week, temps peaked and poor refreezes due to nightly temperature inversions kept the snowpack warm and wet. As a result, widespread wet slide activity can be seen throughout the range on all aspects in terrain steeper than 35 deg. Many popular couloirs slid late last week and are choked with avy debris.

In the McGee Creek drainage, the summer trail is clear from the TH up canyon nearly 2 miles. Descents on the N facing slopes of McGee Creek Peak are well filled in with coverage running down to the creek. The snow surface is transitioning to spring snow from 8000′-10,000′, but not quite there. A few more days of melt and solid refreeze will bring the snow into corn territory from its current state. Above 10,000′, sun crust and powdery wind deposits are still holding on in sheltered, steep N facing nooks.

Similar conditions existed in the Pine Creek drainage further south near Bishop on Sun., 4/14. A cold storm had given the snow a good refreeze and between 1-5″ of new snow on Sat. PM and Sun., 4/13-14, making for great travel and ski conditions. Snow is above the TH and requires a mile or so of walking along the summer trail/old mining road up into the Pine Creek drainage before reaching snow.

Much like McGee Creek, the signs of a rapidly-cooked transitioning snowpack are everywhere as massive wet slides have cleared out most gullies and couloirs. Underneath the light amounts of new snow, the base surface from 8000′-11,000′ was firm and sun affected, yet pleasantly edgeable and fast. Above 10,000′ enough new snow had fallen on Sun. to provide great dust on crust/powder conditions. This new snow will need a few extra days to transition into melt/freeze conditions. Above 11,000′, N facing terrain, couloirs and bowls still host cold, winter snow that will likely prevail for the next week.

In summary, coverage on the Eastside is generally average to just below and snow is well on its way to becoming corny, dreamy goodness. Another week of sunny skies, warm days and cold nights should do the trick.

Weather/forecast thoughts:

No storms are on the horizon for the next week or so as a beautiful spring pattern takes hold over the Sierra. Sunshine and highs approaching 60 each day this week look likely through the weekend. Lows will cool off into the 30s with lower temps in the mountains promoting at least modest surface refreezes. As long as temps cool off sufficiently each night, this could be the week for great corn snow up and down the Sierra.

0600 temp. at 6350′ in Carnelian Bay: 34.1 deg. & 86% RH

Backcountry obs.:

Yesterday morning I toured in the Tamarack backcountry and found widespread supportable spring snow that had received a solid refreeze overnight Tues. – Weds. Temps at the 8650′ TH registered 31 at the car.

Travel was quick and efficient on the firm surface. The surface had been textured by daily melt/freeze cycles making skins grip easily, even on fairly steep uphill runs. Supportable melt/freeze surfaces existed on nearly all aspects from 8650′ to 9200′ atop Galena Peak on all aspects except sheltered or steep N. slopes and gullies.

In those few exceptional areas, breakable transitional crust was abundant in N. facing trees, while soft, moderately dense, old powder existed in a sheltered, 45 deg. N facing chute.

Due to the early hour, the skiing was firm and fast, but likely warmed to buttery corn by 8-10am. If headed into terrain with any consequence, carry a whippet, especially in the morning.

Weather and forecast thoughts:

What looked like a calm, warm, spring pattern late last week is now, yet again getting interrupted by a cold, cut off low this weekend. This skier’s dreams of long, corn descents in a Hawaiian shirt have been shelved for the time being as showers and accumulating snows look likely in the mountains for the weekend.

Today is the last solid, warm spring day in the Sierra until early next week. Highs will get into the upper 50s to maybe 60 around the lake. Expect temps to be a few degrees cooler in the mountains, but on the snow it’ll feel plenty hot.

Tomorrow will be warm, but as the cutoff low from the N approaches, afternoon showers and thunderstorms will likely fire up with initially high snow levels, dropping through tomorrow evening and setting up camp some where in the 6000′ – 7000′ range. S and SW winds will pick up as the low approaches too.

Sat. looks to be the day with the greatest chance for meaningful precip as the low progresses down the CA coast and syncs with daytime warming instability. Areas west of the crest will receive the most snow – maybe up to 6″ or locally more – while Tahoe communities pick up a dusting to an inch or two Sat. pm into the overnight. Scattered showers and cool conditions will prevail into Sun. before tapering off Sun. night into Mon.

As is common in the Sierra in spring, showers and cloud cover will likely increase throughout the day both Sat. and Sun. as convective heating further destabilizes the atmosphere, enhancing showers. Rumbles of thunder and graupel/pellet showers are very possible too. Where the more intense showers set up, especially high in the backcountry, respectable amounts of snow could fall bringing totals up. This is a scenario where cold temps will solidify the corn surface in the backcountry and new snowfall could create a dust on crust, or with some luck, even a sneaky spring powder refresh for the highest elevations and N. facing aspects.

Winds will pick up with this system, making for less than pleasant spring travel through the backcountry. If enough snow falls, wind slabs on lee aspects will be suspect and merit caution.

By Mon., a few lingering showers could fire on the crest, but most areas will see a return to sunny skies and milder temps in the 40s and 50s. Looking into next week, no storms appear in the models just yet, but cooler temps and generally clear skies seem probable as a dominant trough of low pressure settles into the western third of the continent.

It’s not the weekend for Hawaiian shirts, but with some luck, another spring powder session could be in the cards.