The Morning Intel | Tahoe Sector Watch

Location: #HippieHaus | South Lake Tahoe, CA

Date: Sunday, December 21, 2025

¡Buenos días my friends,

Cup'O'Joe in hand, #StokeLevelRising, on a #SoulfulSunday. As I type here at the #HippieHaus, 0431, Roads open, no controls, rain, and winds. Webcams at Palisades, Kirkwood, Bear Valley, Sugar Bowl, and Northstar are all showing rain at base level. Snow levels seem to be hovering around the 8,700' and above levels.KBBX and KDAX radar all show large bands of precip inbound. Latest HRRR 3km Composite + Precip models project the main plume focused to the North of I-80, sliding down across the Sierra over the next several hours.

This forecast has been a humbling journey, a complex puzzle that refuses to be rushed. I will not stand here and fabricate a timeline for when the turn to snow will happen; that transition remains a mystery for now. I haven't lost faith; I am simply releasing the need to control the clock. Why #OverStoke when we can simply be?

I am choosing to stay calm and watch the windows. I'm going to wash the truck, throw on the Hawaiian shirt, break out the flippies, and breathe in the sunrise. In about thirty minutes, I’m heading up to Truckee to take the helm for the Ski California Winter Weather Show from 0700–1000. We’ll be spinning tracks to feed the soul, discussing the atmospheric dance, and checking in live with the crews at Palisades, Sugar Bowl, and Boreal for the ground truth.

Tune in to 101.5 Truckee Tahoe Radio at 0700, and let’s ride the frequency together. Peace, patience, and POW dreams.

Current Sector Data

Regional Temperatures:

• South Lake Tahoe (KTLV) at 6,308': 45ºF (Warm sector firmly in place)

• Truckee (KTRK) at 5,899': 45ºF

• Mammoth Mtn Race (MTH03) at 11,034': 27ºF

• Chair 6 Ridge (9,100'): 34ºF (Hovering just above freezing)

Regional Winds (The Engine Room):

• HippieHaus: 225º (SW) 16mph

• Truckee: 217º (SW) 21mph

• Donner Pass: 221º (WSW) 22mph

• Carson Pass: 237º (WSW) 52/63mph (Ripping)

• Mammoth Race (MTH03): 212º (S) 49mph

Roads (CalTrans @ 0432):

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

• I-80 Truckers: All westbound trucks are required to stop at the brake check area 0.5 mi west of Nyack due to wet brakes/fire risk.

Forecast Update: Atmospheric River & The Trio of Concerns

Comparing the models from yesterday's "Stormy Saturday" to this morning, the intensity has ramped up. We are no longer looking at "potential" impacts; the Atmospheric River (AR) is overhead, and the data has shifted to high confidence regarding moisture content and wind velocity.

1. The Precip: "Pumping Moisture" (Significant Increase)

• Change from Yesterday: Yesterday, we discussed 3-8 inches of liquid. Today, NWS Sacramento reinforces this but specifically notes that probabilities for 10 inches of rain in Butte County (just north of us) are now at 90%.

• Local Risk: NWS Reno highlights a "Moderate Risk" (45% chance) of excessive rainfall near Donner Summit. NBM probabilities give a 70-80% chance of 3+ inches of liquid in these areas through Monday.

• Flood Watch: Remains in effect for the entire Tahoe Basin and Lassen areas.

2. The Wind: Hurricane Force Gusts

• Data Point: The 700mb jet (approx 10,000 ft) is screaming at 75 knots.

• Impact: This translates to ridgetop gusts of at least 100 mph and valley gusts of 50-65 mph.

• Mtn Ops Support: If the lifts are on hold today, give the teams a break. You cannot run a chairlift safely in 100mph winds. Period.

3. The Mid-Week "Miracle" (New Data)

• The Signal: While today is wet, the signal for the Christmas storm has improved significantly.

• The Stats: NWS Reno reports a 60-70% probability for over 1 FOOT of snow at Lake Level (Tahoe Basin) by Friday afternoon.

• Elevation Drop: Snow levels are projected to crash to 5,500-6,000 ft by Wednesday morning.

AFD Comparative Summary: Reno vs. Sacramento

• NWS Reno (REV): Their discussion is broken down into a "Trio of Concerns." They are heavily focused on the immediate Hydrology (flooding) and Wind threat. They explicitly mention the Susan River and West Fork of the Carson exceeding action stage. They also flagged the Winter Storm Watch issued for Tuesday night–Friday.

• NWS Sacramento (STO): Their focus is on the sheer volume of the AR, noting the "deepening trough" in the Eastern Pacific. They emphasize the duration: "Series of atmospheric rivers... through the holiday week." They agree on the high snow levels (>8,000') today but are bullish on the "Season Saving" potential of the mid-week system, citing 70-80% probabilities of >30 inches of snow above 5,500 ft starting Tuesday.

✈️ Aviation Section

Current Status: Impactful.

• Hazards: Low-Level Wind Shear (LLWS) is present area-wide.

• Turbulence: With surface winds hitting 40-50 kts and ridgetop winds at 100 mph, expect severe mechanical turbulence and mountain waves.

• Visibility: KTRK (Truckee) and KTVL (Tahoe) will see visibilities decrease to IFR/LIFR (Low Instrument Flight Rules) later today as rainfall intensity peaks.

• Change: Conditions have deteriorated since yesterday's report; VFR windows are closing rapidly.

⚓ Mariners Forecast

Lake Tahoe:

• ⚠️ WIND ADVISORY: In effect until 4 AM Monday.

• Conditions: The lake is angry.

• Winds: Southwest 20 to 30 mph, with gusts up to 55 mph today.

• Wave Heights: 2 to 5 feet.

• Change: Gust potential has increased from yesterday's 40mph forecast to 55mph today. Ensure all vessels and paddlecraft are secured immediately.

Sierra Avalanche Centers

Central Sierra (Tahoe/Carson Pass):

• Status: Rising Hazard.

• The Bottom Line: New snow is accumulating only above 8,700'-9,000'. This loading on the upper peaks is creating slab avalanche potential. Below that line, the hazard is wet loose instability due to rain.

• Note: Daily forecasts are anticipated to begin Dec 21/22.

Eastside Region (Mammoth):

• Status: Hazard Rising.

• Warning: "Avalanche hazard is expected to rise as a powerful storm impacts our region with intense winds, rain, and snow."

• Tactics: Avoid steep terrain during this storm cycle. The shallow snowpack combined with rain creates unpredictable weak layers.

The Bottom Line:

We are in the "Wash Cycle." Today is about patience, gratitude for the moisture (even if it's liquid), and prepping for the shift. The stats don't lie—the mid-week storm has the potential to deliver feet, not inches. But for today? Put on the Hawaiian shirt, grab that Cup'O'Joe, and tune into 101.5.

Stay'nThirsty for POW,

Coop | RS#69