The Morning Intel | Tahoe Sector Watch

Location: #HippieHaus | South Lake Tahoe, CA

Date: Wednesday, December 17, 2025

¡Buenos días my friends,

Cup'O'Joe in hand, #StokeLevelRising, on a #WisdomWednesday. Well, it's warm—48º here at the #HippieHaus. Windy, Light rain, 34º top of Cornice, winds at ridge line 40/50mph, lakes bumpity, looking like it's a coastal inlet. Reporting and model guidance are all over the map.

Low-down/DL: It's a Wet, Pineapple pipeline, with snow elevations as I type (if any) above 9,500'. As we discussed yesterday, prognosticators dropping snow totals and elevations—BEWARE.

Today: Rain is most likely late morning into early afternoon (about 10 AM–1 PM). Snow levels remain very high early, then may, may, drop to near 8,200 ft by afternoon. Expect a high close to 49°F. It'll be breezy to windy, with southwest winds 20–25 mph and gusts up to 45/50 mph. Precipitation chances are high (90%), with total liquid amounts generally in the 0.25" to 0.50" range.

Forward lens: Another wave of precip - 'could', 'might', 'possibly', 'maybe'—bring heavy rain/snain/snow Friday night through Sunday, with #GorillaSnot confined to elevations above 9,000 ft. Looking ahead, colder storms remain possible by Christmas Eve and into the final week of December.

Current Sector Data

Regional Temperatures:

• South Lake Tahoe (KTLV) at 6,308': 48ºF (Tropical feel in the basin)

• Truckee (KTRK) at 5,899': 45ºF

• Mammoth Mtn Race (MTH03) at 11,034': 30ºF

• Chair 6 Ridge (9,100'): 34ºF (Barely freezing)

Regional Winds:

• HippieHaus: 224º (SW) 23mph

• Truckee: 239º (WSW) 18mph

• Donner Pass: 228º (SW) 40/45mph

• Carson Pass: 224º (SW) 40/55mph (Cranking up top)

Roads (CalTrans @ 0432):

• Sierra Sector: ALL CLEAR (SR88, Hwy 50, I-80).

• I-80 Truckers: Westbound brake check mandatory 0.5 mi west of Nyack.

Forecast Update: The Pineapple Express & The Break

We are living the reality of the "#RainyDay" today. Comparing the AFDs (Area Forecast Discussions) from Reno and Sacramento, here is the breakdown of the changes and the scientific reality vs. the hype.

1. Today's Reality: Wind & Rain (The Wash Cycle)

• The Change: Yesterday, we tracked the onset; today, we are in the moisture tap.

• Snow Levels: NWS Reno confirms snow levels remain high, generally above 9,000 ft, limiting significant snow to only the highest peaks (White Mtn, Mt. Rose Summit). NWS Sacramento notes snow levels might dip toward 8,000' Saturday, but for today, it's liquid.

• Wind Event: Wind Advisories are active until 4 PM. We are seeing robust 700mb flow (50-65 kts). Expect Ridge Gusts of 80-100 mph today. This could/might impact lift operations significantly.

• Nuance: NWS Sacramento maintains a 10-25% chance of Thunderstorms this morning, adding a dynamic "instability" layer to the rain.

2. The Thursday Pause

• Update: Weak ridging returns tomorrow (Thursday). This is your window. Conditions dry out, winds drop significantly. If you need to fix a tarp or check the boat, Thursday is the day.

3. The Weekend & Christmas Outlook (The Miracle?)

• The Setup: Another system approaches Friday, bringing gusty winds back.

• The Hope: While it starts warm, confidence is increasing for significant snowfall at higher elevations (above 7,000 ft) later in the weekend as colder air filters in.

• The Long Game: Both NWS offices agree the pattern favors Atmospheric River (AR) events leading up to Christmas. The storm door is wide open.

Impacts & Action Items

🏔️ Mountain Operations (The Real MVPs):

Today is going to be a battle for the Mtn Ops teams. They are dealing with Rain on Snow (ROS) at the base, 100mph winds on the ridge, and potential lightning holds.

• Authenticity Check: Grooming wet, heavy slush is an art form. Doing avalanche control when the snowpack is turning to #GorillaSnot is exhausting. Give these teams a high-five or a beverage when you see them. They are saving the base for the colder storms ahead.

❄️ Backcountry / Slednecks:

• Hazard: Rain on Snow at high elevations creates a nasty, wet-loose avalanche problem. The snowpack is shallow, and obstacles (rocks/stumps) are just below the surface.

• Sierra Avalanche Center: "Very high elevation rain on snow could create wet snow avalanches this week." Know before you go.

✈️ Aviation Section

Current Status:

• MVFR conditions are likely as rain showers, lower ceilings, and visibility at Tahoe and Sierra Front terminals.

Forecast:

• Turbulence: Mountain Wave Turbulence and LLWS (Low-Level Wind Shear) are the primary concerns through this evening. FL100 winds are screaming at 40-60 kts.

• Surface Winds: Gusts 35-45 kts at RNO/CXP/MEV.

• Outlook: Conditions improve Thursday, then deteriorate Friday again with the next system.

⚓ Mariners Forecast

Lake Tahoe:

• Advisory: WIND ADVISORY in effect until 4 PM PST.

• Today: Showers, slight chance of Thunderstorms. Southwest winds 25 to 40 mph with gusts to 65 mph.

• Wave Heights: 2 to 6 feet. (This is serious water for Tahoe. Do not underestimate 6ft waves in a short-period lake swell.)

• Tonight: Winds decrease slightly (Gusts to 30 mph). Waves dropping to 2 feet.

The Bottom Line: We are in the "Wash Cycle" of this pattern change. Today is about battening down the hatches, dealing with the wind/rain, and letting the warm air do its work to erode the ridge. Thursday gives us a breather, and then we reset for the next wave on Friday.

We need the precip, even if it's wet. It primes the pump. Keep the faith for those dropping snow levels next week.

Stay'nThirsty for POW,

Coop | RS#69