Tahoe Weather


Lake Tahoe succumbed to Coronavirus mitigation in a big way last weekend. Just before lucrative Spring Break week and as the juiciest storm of this sketchy winter season was rolling in, Vail Resorts decided to close their three popular ski areas in the region — Northstar, Heavenly Valley and Kirkwood — due to the virus and its potential health impacts on their employees and guests: Other resorts, big and small, corporate or privately-owned, briefly resisted the sudden and unprecedented move, but then quickly fell in domino fashion.

Cross-country and back-country alpine skiing, snowshoeing and snowmobiling are still robust outdoor activities to be enjoyed, especially in all the fresh snow falling this week, but they represent a minuscule fraction of the region’s important winter economy. As a final nail in the coffin, brew pubs, bars, wine tasting rooms, casinos and restaurant dining rooms are closing too. Wow! So that’s where we stand.

Let’s roll back the tape and review how this winter played out up to this point. Here’s a quick photo essay:

A Sept. 29 snowfall got the juices flowing for an early winter, but the next two months were warm and bone dry. In early November, Squaw Valley fired up its snow-guns although warm temperatures limited production. This is the base-area beginner area for little tykes. The weather-protected moving carpet conveyance whisks kids along as young as 3 up for their first lessons.

A parade of cold winter storms beginning Thanksgiving weekend did wonders for skiing and riding conditions at Tahoe resorts. Squaw Valley looking good for early season.

High pressure in January 2020 kept storms away, but let low-level stratus clouds form due to temperature inversions. In a mixing atmosphere it’s warmer at the surface and the air temperature cools with altitude. An inversion reverses that temperature profile and the colder air near the surface triggers the formation of ground or low-level clouds. This photo from Diamond Peak ski resort shows an inversion-cloud formation over western Nevada looking south.

Low-level inversion clouds in the Tahoe Basin on January 25, 2012. I took this image from the Mt. Rose Highway under a full moon. Looking west with Squaw Valley in distance on right.

After a record-setting February with virtually no rain or snow, on March 14 the National Weather Service warned that the biggest storm of the winter was heading to the Sierra. This was not a jet stream-driven cold front barreling through, it was a slow-moving system that was going to drift around for awhile giving it time to put down some decent snow and precipitation. In fact, it’s still overhead but weakening today. (March 19, 2020).

In three days, the Sierra snowpack improved markedly, but the regional watershed is still suffering a severe water deficit. There are more cold and wet storm systems expected in the first part of next week, but the pace will have to pick up to erase the hydrologic deficit and make this a proverbial “Miracle March.”

Associated Press photo from Heavenly Valley after the storm’s first snowfall had really improved skiing conditions in the Tahoe Sierra — with much more to come. Unfortunately, due to the Coronavirus pandemic, within days all resorts had closed for the season.

This graphic is courtesy of Jan Null, owner of Golden Gate Weather Services. A quick look confirms that parts of southern California got its fair share of precipitation this winter, but the most vital watershed and reservoir systems are all in the north state. The 55% bubble in the northern Sierra Nevada represents the 8 Station Sierra Index, the critical aggregate of 8 important precipitation gauges on the Sierra west slope. Conditions are even more desiccated in the southern Sierra.

View past the historic Thunderbird Lodge on the point looking towards Mt. Tallac and the beautiful, high-elevation Desolation Wilderness area, circa January 2020. There may be a nasty bug skulking around, but nothing can take away from the breathtaking beauty of a Lake Tahoe winter. Even a sketchy one.


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Tahoe Weather


It’s no secret that it’s been a very stormy winter in the Tahoe Sierra. In fact, snowfall totals during the month of January set new records at Donner Pass, Tahoe City and most ski resorts. But the real story in winter 2017 is hydrologic. Nearly a dozen Pacific-bred Atmospheric Rivers have produced phenomenal amounts of precipitation in a short period of time.

If you look to the far right-hand side of the graph, you can see how much more snow fell this January at the Central Sierra Snow Laboratory near Donner Pass than the preceding 45 years’ worth of Januaries. The 237 inches of snow blew away the old Jan. record set at the Lab in 1982. It also easily beat the all-time monthly snowfall record there, measured during the “Miracle March” of 1992.

Carnelian Bay is definitely not the snowiest location in the Tahoe Basin, but it has has really piled up this winter in the "banana belt." Peak ridge wind gusts this February reached 199 mph! The strongest storms that crash into the Tahoe Sierra reach Category 3 Hurricane strength. 

January's heavy snowfall set the stage for long power outages, extensive road closures and frequent avalanches.

Resort totals are impressive: Alpine Meadows & Squaw Valley report more than 47 feet so far. Mt. Rose, where its high elevation converts mild AR rain to snow, leads regional ski areas with nearly 54 feet. Snowpack base amounts at Tahoe Basin resorts range from 8 to 22 feet deep.

In 2015, many streams, rivers and reservoirs in Northern California were near record lows; today officials are releasing torrents of water to make room for the looming spring melt of the massive mountain snowpack. The current “snow water equivalent” (SWE) in the expansive Northern Sierra pack is approaching 6.5 feet. At this time the federal water master for Lake Tahoe is releasing 500 cubic feet-per-second out of Big Blue to make room for the coming melt.

In early December 2016, the outlet of Lake Tahoe was just dirt with a lake level below the natural rim. Since October 1, Tahoe has risen nearly 4 feet and is now at 6,226.81 feet above mean sea level. Approximately 139 billion gallons of water have been added to Big Blue so far this season. That’s enough to supply the average annual water consumption for 435,500 four-member households. 

These piers were high and dry last year. Given that the snow water equivalent (SWE) of the Tahoe Basin snowpack is more than 230% of normal, it’s a foregone conclusion that the lake will rise to its maximum legal limit by this summer. It will be the first time since 2006.