Tahoe Backcountry Snow

0530 wx. at 6350′ in Carnelian Bay: 34.2° / 31.8° dew point / 91% RH / mostly clear skies

Backcountry obs.:

Light snow showers transitioned to rain up to 9000′ before ending late Sat (3/22) and temps since then have remained warm, even at higher elevation areas. Sun (3/23) high temps peaked in the mid 40s up to 9600′ and haven’t fallen below freezing since. Sensors this morning (3/24) show above freezing temps across the central Sierra, even up to 11,000′.

The abrupt transition from cold to warm hasn’t allowed a melt-freeze cycle resulting in wet, sticky snow with plentiful free water in the upper snowpack. Skiing has turned abruptly wet and sloppy with wet snow instabilities widespread in the backcountry. The next few days will get even warmer with highs well into the 50s by midweek, before cooler, unsettled weather returns toward the latter half of the week.

Weather and forecast thoughts:

The next few days will be unseasonably warm with late spring high temps reaching the 50s and lows falling into the mid-upper 30s the next few nights (3/24-26). Sunshine will prevail as well, further baking surface snow on solar aspects. Be on the lookout for sloppy skiing and loose/wet avalanche problems, especially in the late morning and afternoon as the snowpack adjusts to rapid warming, possibly becoming isothermal.

The big heat up does have an expiration date. Looking ahead, models show the spike in temps being short-lived, followed by a generally cool and unsettled pattern returning by the end of the week and continuing into the first week in April.

Rain and snow shower chances enter the picture on Thurs (3/27) and continue off and on through the first half of next weekend. Most of the energy with these systems will head north into the PacNW, but the Sierra will see a return to freezing temps and some modest snow accumulations in the backcountry.

By Sunday (3/30) a more significant wave could bring more significant snows and colder temps, potentially resetting the snowpack. The pattern for the first week of April continues the trend of cold and unsettled as a large, upper level trough centered over the NE Pacific begins moving into CA, bringing chances for more potent storms to keep winter going for a little longer.

0400 wx. at 6350′ in Carnelian Bay: 32.4°F / 32.0°F dew point / 98% RH / overcast with light snow / 4″ 24hr. snow total

0515 wx. at 8400′ Mt. Rose backcountry TH: 26°F / overcast with mod. snow / gusty SW winds / 7″ new snow total

0645 wx. at 9500′ in Mt. Rose backcountry: 22.2°F / 22.1°F dew point / RH 100% / SW wind @ 5-10mph, gusting 15-20mph / overcast with light/mod. snow / 12-14″ new snow

Backcountry obs.:

This morning was a full-on storm morning. Moderate snow and gusty, erratic winds raked the Mt. Rose backcountry at dawn. New snow and wind had completely covered the mangled snow surface of a weekend’s worth of powder hungry traffic.

Throughout open areas near 8400′, 7″ of fairly dense new snow rested atop imperceptible suncrusts. New snow amounts increased with elevation throughout sheltered NE aspects up to treeline at 9500′, where up to 14″ of new snow had fallen overnight. Stiffened wind pillows and freshly sculpted cornices adorned treeline ridges.

Wind effected snow did not react to stomps and ski cuts. The new snow appeared fairly well-bonded to old snow surfaces as no cracking, whumphing, or other obvious signs of instability grabbed this skier’s attention on the up or down.

Skiing just after dawn awakened every synapse with glorious, soft, light surface powder providing quick sliding atop slightly denser early storm snow. It was yet another morning of the season’s best turns: smooth, soft, and springy, adorned with flashes of white smoke. If only the mountain had 3000′ more vertical.

Weather and forecast thoughts:

While seemingly slow, blustery, and warm at the start, today’s (3/17) St. Paddy’s Day storm ended up bringing another round of excellent snow to the Tahoe backcountry. Falling temps behind the early morning frontal passage and an unstable airmass have kept moderate-heavy snow showers firing throughout the day, adding considerable accumulations to backcountry zones. Total accumulations by this evening could easily reach 1-2’+ above 7000′ with the highest amounts along the crest.

Tonight snow showers will taper and skies will clear soon after sunset with temps. falling into the single digits to low 10s above 7000′ by daybreak.

Tomorrow (3/18) a transient ridge of high pressure will begin building into the area warming temps and clearing skies. High temps above 7000′ will reach the upper 20s to mid 30s tomorrow under bluebird, sunny skies.

Calm, clear, and milder weather is in store for Wednesday (3/19) with temps climbing into the middle-upper 30s, before another, more modest storm system enters the picture for Weds PM into Thurs AM.

Models currently show this system brushing by Tahoe and favoring areas north and west of the lake with a few quick inches of surface refresh by Thurs AM (3/20). Stray snow showers may linger and briefly build in the mountains throughout the day Thurs with highs climbing into the low to mid 30s across the backcountry.

Winter’s March comeback will begin to fade late this week as springtime weather nudges its way into the Sierra. Sunshine, warmer temps, and a generally benign pattern return Fri though the weekend (3/21-23). Temps on Fri will climb to near 40 and warm a few degrees with each successive day this weekend as a ridge of high pressure builds in. Nights should cool below freezing each day, initiating a new corn cycle that will transform the recent fresh powder into creamy corn.

Looking into next week, the ridge of high pressure continues building through at least mid-week, warming temps further. By the end of the week, ensembles suggest a return to unsettled winter weather with a long wave trough of low pressure moving in from the Gulf of Alaska accompanied by cooler temps and chances for more snowfall.

0800 wx. at 6350’ in Carnelian Bay: 22.3° / 20.7° / 94% RH / 11” new snow / calm winds / overcast skies w/ snow showers in vecinity

Current 6350′ wx. notes:

The storm came in late yesterday (3/12) afternoon and delivered a burst of heavy snow meeting forecast expectations: 11” total.

Today more snow will fall in convective showers throughout the day with peak intensities this afternoon. Another 3-6” can be expected above 7000’ in highly localized bands of showers. High temps will stay cold with teens and 20s in the backcountry, low 30s around 6000’. Tonight will be cold with a few lingering showers adding light accumulations.

Another shortwave comes in tomorrow morning delivering up to a foot above 7000’ with several additional inches possible at lake level. High tomorrow will remain cold with highs in the 20s for backcountry zones, low 30s near 6000’.