Road conditions changing on day that has brought snow, rain, thunder snow to Lake Tahoe

SOUTH LAKE TAHOE, Calif. - Chain controls have been lifted on several Lake Tahoe area roads, but that doesn't mean the snow storm is over. January 20 has been a day full of weather, from rain and thunder snow, to white-outs at the ski resorts and breezy conditions.

Both Kirkwood and Heavenly Ski Resort had to close some ski lifts earlier today after lightning was striking in the area and Sierra-at-Tahoe closed early due to high lightning potential.

Thunder snow is unusual in the Sierra Nevada according to the National Weather Service (NWS) in Reno. It is just like a summer thunderstorm but the precipitation is snow instead of rain. NWS said it is caused by an instability in the atmosphere with upward vertical motion. Particles get charged and hit each other, and the charge of this motion causes a crack, and thunder.

"You have to have intense, unstable conditions," said the NWS in Reno. "It is more common on the East Coast with Nor'easters."

Once the thunder snow passed, upper elevations saw white-out conditions. Chain controls are down on US50 at 3:30 p.m. but this can change at any time.

Remaining chain controls at this time:

I80 - Chains Required, All Vehicles Except 4-Wheel Drive with Snow Tires - on I-80 from mile post 63.5 in Placer County to mile post 14.2 in Nevada County in California.

SR89 - Chains Required, All Vehicles Except 4-Wheel Drive with Snow Tires - on CA-89 from mile post 21.4 in Alpine County to mile post 6.7 in El Dorado County in California.

SR88 - Chains Required, All Vehicles Except 4-Wheel Drive with Snow Tires - on CA-88 from mile post 58.7 in Amador County to mile post 13.4 in Alpine County in California.

SR207 - Chains Required, All Vehicles Except 4-Wheel Drive with Snow Tires - on SR-207 from Dagget Pass Chain-Up Area to mile post 7.0 in Douglas County in Nevada. Chains Required, All Vehicles Except 4-Wheel Drive with Snow Tires - on SR-207 from US-50 Junction to Dagget Pass Chain Up Area in Nevada.

US395 - Chains Required, All Vehicles Except 4-Wheel Drive with Snow Tires - on Alt US-395 from mile post 0.0 in Washoe County to mile post 7.22 in Washoe County in Nevada.

Oversized Load (Minor Delays) - on SR-88, SR-206, SR-757, US-395/I-580, US-50, US-95, US-95A, SR-360, US-6 from the CA/NV state line to the NV/CA state line in Nevada. Escorted Load. Daytime Hours only. Estimated End Time is 6:00 PM on 01/22/19

For more on current road conditions, visit http://quickmap.dot.ca.gov/ for California conditions and https://nvroads.com for Nevada.