The Morning Intel | Tahoe Sector Watch

Location: #HippieHaus | South Lake Tahoe, CA
Date: Thursday, December 25, 2025
Time: 0655 PST

¡Buenos días my friends,

Merry Christmas! Cup'O'Joe in hand, #StokeLevelPinned at 13.7, as our wish and hope for a White Christmas has come to life. We have 6" on the deck here at the #HippieHaus (elev: 6,350’) with light snow flurries flyin’. Looking at the resorts, the upper elevations saw 13"-16" in 24hrs—some a bit more, some a bit less, but around 13/16". I heard numbers like 24", and I hope they did, we’ll see as the morning reports roll in.

HOWEVER, today we are on schedule to receive periods of heavy Sierra snow, significant mountain travel disruptions, and peak gust winds (peaks at 0400 around Round Top at 9,100’ were 85.9 sustained / 108.7mph gust). Snow impacts may spread into the western Nevada foothills Christmas night into Friday morning.

Mtn Ops teams are “turning-to” to get as much terrain open as safely as possible for us all to get out and enjoy. It’s a lot of work in a short time, with the next-round of #MaNatural at the door as I watch KDAX and KBBX radar.

On the roads: #Slow’yrRoll - I-80 was a junk-show yesterday. TRK & Donner CHP are working OT to clean up the messes with the CalTrans krews. Give’m a break, and the space needed to work safely. It’s HUG a CHP and CalTrans driver day :)

Back Country: Just go to the SAC site and read. Pretty easy decision: let’r settle and set up for a day. Links are below for both Central and Eastern forecasts.

It’s Christmas morning, and we, Carolyn and I, wish you all and your families the best today, and in the Year ahead. As my friend, the Dalai Lama, once said:

“Every day, think as you wake up, today I am fortunate to be alive, I have a precious human life, I am not going to waste it. I am going to use all my energies to develop myself, to expand my heart out to others; to achieve enlightenment for the benefit of all beings. I am going to have kind thoughts towards others, I am not going to get angry or think badly about others. I am going to benefit others as much as I can.”
― The Dalai Lama

Tahoe Sector Data (Verified @ 0655 PST)

Regional Temperatures:

• South Lake Tahoe (KTLV) at 6,308’: 33ºF (Freezing line established)

• Truckee (KTRK) at 5,899’: 32ºF

• Chair 6 Ridge (9,100’): 23ºF (Proper Winter)

• Mammoth Mtn Race (MTH03) at 11,034’: 16ºF (Deep Freeze)

Regional Winds (The Engine Room):

• HippieHaus: 186º (S) 20mph

• Truckee: 178º (S) 20mph

• Donner Pass: 181º (S) 23mph

• Carson Pass: 184º (S) 66 sustained / 87 gust (Hurricane Force - Major Lift Impact)

• Mammoth Race (MTH03): 189º (SSW) 45mph

Roads (CalTrans @ 0630):

• Status: MESSY, SLICK, NASTY.

• I-80: CLOSED to Tractor-Semitrailers (Applegate to State Line) due to multiple spinouts. R2 Chains for all others.

• SR88: R2 Chains (6.5 mi east of Peddler Hill to 1 mi west of Woodfords).

• HWY 50: R2 Chains (Twin Bridges to Meyers).

• Coop’s Note: If you don’t have 4WD and snow tires, you are chaining up. Don’t be the guy that blocks the road on Christmas.

• CalTrans QuickMap: https://quickmap.dot.ca.gov/

Forecast Update: Analysis of Changes (REV vs. STO)

⚠️ Active Advisories:

• WINTER STORM WARNING: In effect until Friday, 10 AM. (Sierra & Lake Tahoe)

• WIND ADVISORY: Active for lower elevations / NV Valleys (4 AM - 10 PM).

• FLOOD WATCH: Remains active for lower elevations; cancelled for the Sierra as precipitation has transitioned to snow.

The NWS Deep Dive (Forecast Evolution):
We are shifting from yesterday’s “Transition” narrative to a distinct “Two-Wave” event. The uncertainty regarding when the snow levels would drop has been replaced by real-time data showing a complex storm structure.

1. The “Two Wave” Structure (NWS Reno):

• Wave 1 (This Morning): Heavy snow continues through noon. The “White Christmas” criteria (1"+) has been met.

• Wave 2 (Tonight - Friday AM): This is the critical update. A second, colder, and more unstable wave arrives late tonight. NWS Reno explicitly states that while confidence in exact snow levels is variable, they are now forecasting snow accumulation down to the Western Nevada Foothills (Virginia City/Reno) by Friday morning.

2. The Severe Weather Threat (NWS Sacramento):

• The Change: Yesterday mentioned “isolated thunderstorms.” Today, the language has intensified.

• The Detail: NWS Sacramento is tracking a specific window for “Severe Storms” between 01Z and 05Z (5:00 PM - 9:00 PM PST tonight).

• The Nuance: Parameters show up to 500 MUCAPE (Convective Available Potential Energy). This implies a very unstable atmosphere where a “stray severe storm” cannot be ruled out. This energy acts like a turbo-charger for snowfall rates, supporting the forecast of 3-4 inches per hour in localized bands tonight.

3. Hydrology Note (Susan River):

• The Risk: NWS Reno notes that additional rain this morning before the transition to snow could cause a second rise on the Susan River. A tiny difference in the snow line (e.g., 500 feet) determines whether the river floods again or recedes.

✈️ Aviation Section

Current Status: LIFR

• Conditions: No-Go Day. Heavy wet snow is hammering the terminals.

• Accumulation: NWS Reno cites an 80% chance (very high confidence) of 6+ inches of accumulation on runways at KTVL (Tahoe) and KMMH (Mammoth) by this afternoon. KTRK (Truckee) has a 40% chance of >3 inches.

• Hazards: Freezing Fog and severe Mountain Obscuration. Ridgetop winds are gusting 80-100 mph, creating severe mechanical turbulence and Low-Level Wind Shear (LLWS).

⚓ Tahoe Mariners Forecast

• ⚠️ WINTER STORM WARNING: In effect until Friday 10 AM.

• Today: Heavy snow. Freezing Fog reducing visibility to zero.

• Winds: South 20-30 mph, gusts to 45 mph.

• Tonight: It gets gnarly. Southwest gusts increasing to 55 mph.

• Wave Heights: 2 to 4 feet.

• Coop’s Warning: Dense freezing fog and 55mph gusts make the lake incredibly dangerous today. Stay on the dock.

Sierra Avalanche Centers

Central Sierra (Tahoe/Carson Pass):

• Status: Danger Rising Quickly.

• The Bottom Line: Unstable slabs of new snow are forming rapidly in wind-loaded areas. The danger will spread to sheltered terrain as the storm intensifies.

• Link: Sierra Avalanche Center Forecast

Eastside Region (Mammoth):

• Status: Very Dangerous.

• The Bottom Line: “Avoid being on or under steep, wind-loaded slopes.” The new snow is sitting on bare ground in many places, meaning obstacles (sharks) are a major hazard.

• Link: Eastern Sierra Avalanche Center Forecast

The Bottom Line: It is a proper Sierra Christmas. We have feet of snow falling, hurricane winds, and a storm that isn’t quitting until Friday. The “Wave 2” arriving tonight packs the biggest punch, so don’t let a lull this afternoon fool you. Enjoy the family time, keep the fire roaring, and let the Mtn Ops teams do their work. The skiing tomorrow and into the weekend is going to be all-time.

Merry Christmas & Stay’nThirsty for POW,

Coop | RS#69