Avalanche! Tahoe Weather Weather History

#230 WINTER OF 1982


It’s been 30 years since one of the deadliest avalanches in Sierra Nevada history broke loose at Alpine Meadows Ski Resort and killed seven people. For those of us who remember this tragic event on March 31, 1982, and the days of grief and hope that followed, it represents a benchmark in time. The 15.5 feet of snow that fell at the Central Sierra Snow Lab between March 27 and April 8, 1982, still ranks as the greatest single snowstorm total on record for Donner Summit.

Miraculously, Alpine Meadows employee Anna Conrad survived for 5 days in the avalanche debris before she was rescued. She lost parts of both legs to frostbite, but after the surgery she was fitted with prosthesis. Today, she and her husband reside at Mammoth Lakes, California, where Anna is employed as a snow hostess for the resort.

Anna (Conrad) Allen survived the 1982 avalanche at Alpine Meadows. She suffered frostbite injuries, but later moved to Mammoth Mountain where she lives with her husband.

For anyone who skis or snowboards today, whether backcountry or controlled resort, the 1982 avalanche still serves as a reminder that the rugged mountains and dynamic weather we love so much are powerful forces of nature that deserve respect and understanding.

Read a short version of the story here: Tahoe Nugget #60

The winter of ’82 was also noteworthy for an extreme precipitation event that occurred in January. From Jan. 3-5, torrential rains caused extensive damage and destruction in the lowlands of the central and northern parts of California and heavy snows fell in the highest mountains. The San Francisco-Bay Area experienced the heaviest rainfall in 25 years. On January 4, San Francisco was doused with 6.16 inches of rain which is still the greatest one day storm total there in 159 years of rainfall records. 

The Santa Cruz Mountains were inundated with 10 to 20 inches of rain in 30 hours. The National Weather Service reported more than 8 inches of rain in one day there, the greatest 24-hour rainfall since 1890 when record keeping began. Considered one of the worst storms of the century, several thousand people were flooded out of their homes and at least 33 killed. Trains derailed, schools and highways were closed, and damage was estimated at $300 million.

Avalanche path near Mt. Tallac at South Lake Tahoe.

When the saturated air mass encountered the Sierra Nevada, precipitation intensified due to topography and orographic enhancement. The Echo Summit weather station at Sierra Ski Ranch, elevation 7,450 ft., is approximately ten air miles southwest of South Lake Tahoe, on the upper western slopes of the Sierra Nevada. The station is located near the Sierra Nevada crestline in an area where the well-defined ridge has a northwest-southeast orientation. Situated on a north-facing slope, the site is a choice area for maximum snowfall production.

24-hour snowfall of 67 inches set a new California record in January 1982.

Weather maps of this event indicated a strong zonal flow with very moist air moving west to east across the Eastern Pacific. This juicy fetch of moisture from the southwest collided with colder air flowing down the eastern side of a high-pressure system centered over the Gulf of Alaska. At Echo Summit, 67 inches of snow (5.6 feet) fell in just 24 hours, which ranks it as the second greatest single day snowfall total in the United States. The North American and world records are held by Silver Lake, Colorado, which received 76 inches (6.3 ft.) in 24 hours on April 14-15, 1921.

Overnight snowfall in the “banana belt” neighborhood of Gateway west of downtown Truckee.

The Jan. 4-5 storm that dumped up to five feet of snow in the mountains was only one in a series of powerful snowstorms that had been hammering the Sierra Nevada over the New Year’s Holidays. The Central Sierra snowpack exceeded 11 feet in depth, and nearly a dozen avalanches had roared through the Donner Summit. Thousands of motorists were stranded when highway crews shut down Interstate 80. The two-day total of 80 inches (Jan. 3-5) recorded at Echo Summit during this 1982 event ranks third in California.

The Tahoe snowpack was huge by mid-April 1982. My brother Tom came out for a visit in March and ended up staying an extra week because we couldn’t get to Reno for a departure flight.

Interestingly, just three months after the Jan. 1982 event, on March 30-31, a 65-inch snowfall was recorded in 24 hours at Twin Lakes, California, only eight miles south of Echo Summit. The two-day total from March 30 to April 1, 1982, at Twin Lakes was 90 inches, the second greatest 48-hour snowfall total in U.S. history.

On January 11-12, 1997, Montague, New York, located just east of Lake Ontario, reported a new record of 77 inches in 24 hours. The measurement was disallowed, however, after the National Climate Extremes Committee determined that the total was achieved by adding six measurements together, two more than the maximum allowed during any 24-hour period.


 Town of Truckee during the big storm that caused the Alpine Meadows avalanche.

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Central Sierra Climate Change Weather History



Around 1960 a secret United States military installation known as Camp Century was constructed 40 feet below the surface of the Greenland Ice Cap. Built by the U.S. Army Corps of Engineers, the camp was powered by the Army’s first field nuclear power plant. Camp Century represented a cutting-edge laboratory where scientists conducted experiments such as radio communications; food preservation; special medical and healing problems; over-ice and under-ice transportation; and the development of better fabrics for cold weather protection. They also wanted to grow fruits and vegetables using ultraviolet lights and try hydroponic farming under the ice.

Camp Century was powered by the PM-2A, the U.S. Army’s first portable nuclear power plant.

Surprisingly, this wasn’t the first time humans had tried to survive the severe weather on the Greenland Ice Cap by burrowing below the surface. During the winter of 1930-31, German Astronomer and Meteorologist Alfred Wegener spent the winter there, living and working in a subsurface shelter he cut out of the ice. Unfortunately, it was Wegener’s last Greenland expedition as he died there of heart failure due to the strenuous environment. Camp Century, however, was much more sophisticated than a simple hole in the ground as it housed a complex of barracks and laboratory buildings in four different levels of ice tunnels, and accommodated up to 250 persons. As a multi-purpose lab, the camp supported nearly 100 research projects over a two-year time span.

Among the projects underway at Camp Century was the development of over-snow tranportation vehicles. Large tires provided a measure of safety against falling into crevasses and “float” over loose snow.

Two of the “Ice Worms,” as Camp Century residents were called, were Dr. Robert W. Gerdel, a physicist and engineer who established the Central Sierra Snow Laboratory (CSSL) at Norden, California, in 1946, and B. Lyle Hansen, another brilliant scientist who also conducted research of the Sierra snowpack at the CSSL. As the lead environmental researcher at Camp Century, Dr. Gerdel played an important role in many ambitious projects tested there, including tunnel stabilization technologies, experimental aircraft landings on ice and snow, as well as continuing the snow physics research he had started at the CSSL on Donner Pass.

As lead research scientist at Camp Century, Dr. Robert Gerdel brought expertise and experience he gained from years studying the Sierra snowpack on Donner Pass. Despite being deaf from a botched tonsillectomy operation when he was a boy, Gerdel enjoyed a long and accomplished career as America’s Chief  of the Climatic and Environmental Research Branch for the U.S. Army’s Snow, Ice and Permafrost Research agency. 

Physicist Hansen earned assignments in Greenland that included developing a radiometer system to detect potentially deadly, hidden crevasses in the ice sheet, and engineering the first thermal drill with a hollow, electrically heated head to demonstrate the feasibility of recovering samples from deep within the ice sheet. The yearly layers in the extracted cores can be dated both by counting each layer — much as the age of a tree is determined by counting its growth rings — and by isotope dating of bubbles of ancient air trapped when the ice was formed.

Thermal drill in operation in Camp Century ice tunnel.

The data obtained in these early drilling projects led to the discovery of previous, rapid climate change cycles and represented a huge leap forward in the science of paleoclimatology. The discovery of natural oscillations in greenhouse gases found in the trapped air of polar ice was considered one of the most important advances in the field of climate and earth science at that time.

Scientists B. Lyle Hansen (left) and Chet Langway study an ice core sample extracted from the Greenland Ice Sheet. The CRREL emblem on their jackets stands for Cold Regions Research and Engineering Laboratory, a scientific agency based in Hanover, New Hampshire. (A more recent core extraction in Antarctica drilled in 2001 and 2002, chronicled climate there back 800,000 years, which includes our most recent ice age and seven more before that.)

Within a few years of the initial drilling at Camp Century, scientists had bored down from the surface of the Greenland Ice Sheet nearly two miles to its bedrock interface, and removed an ice core that represented 110,000 years of climate data. Hidden in the deep layers of ice were samples of the earth’s ancient atmosphere, clues to volcanic and climatic factors that led to past ice ages. Scientists learned that past climates have been wildly variable, with larger, faster changes than anything industrial or agricultural humans have ever faced. Triggers that have caused dramatic climate change include changes in the tilt of the Earth’s axis, wobbles in its orbit, surges of great ice sheets, and sudden reversals in ocean circulation, among others.

Engineers at Camp Century filled over-sized tires with fuel so they wouldn’t have to haul drums of it on sleds behind their vehicles as they traveled across the ice sheet.  Once the fuel was consumed, the tires were filled with air.

Anthropogenic global warming is a hot topic these days, and scientists often look to the distant past to see what may lie ahead in the future. Much of what we know about prehistoric climate is due to the hard work conducted by Camp Century Ice Worms like Dr. Robert Gerdel and B. Lyle Hansen, two men who cut their teeth on Sierra snow.

Entrance to Camp Century. One of the reasons that the operation was shut down was because the constant movement of the Greenland Ice Sheet destorted the tunnel system and required personnel to regularly shave ice from the deformed walls and ceilings.

For more info on Dr. Gerdel’s work at the Central Sierra Snow Lab, click here:





Central Sierra Climate Change Weather History



Fifty years ago, a secret United States military installation known as Camp Century was constructed 40 feet below the surface of the Greenland Ice Cap, just 800 miles from the North Pole. The remote outpost, buried deep under Arctic ice, was manned by more than 200 American military personnel and civilian scientists.

Camp Century’s subterranean location beneath the ice cap protected the men from some of the harshest weather on the planet. The close-knit group of academics and enlisted men stationed there conducted innovative scientific studies and breakthrough climate research in a labyrinth of rooms and tunnels embedded in advancing glacial ice.

Signs with mileage distance are posted for major cities at the subterranean Camp Century beneath the Greenland Ice Cap.

Planned as a self-sufficient, autonomous community, Camp Century represented a “moon colony” on Earth. Construction on the strategic project began in 1958 and the facility was operational by 1960. An elaborate military experiment, Camp Century was laid out with tunnels, dorms, a hospital, library, movie-theater, and other recreational amenities.

Trenches were cut using a Swiss snow miller which blew pulverized ice up to the surface. The milled snow was shoveled onto sheet metal panels arched over the tunnels where it froze solid as concrete. The water and sewage operation was unique in the world. Storms at the surface could generate wind gusts to 125 mph, with ambient air temperatures at minus 70 degrees. Despite wind chill factors nearing 150 degrees below zero, the personnel stationed at Camp Century went about their business in relative comfort.

This Swiss-made snow miller was designed to clear railroad tracks. At Camp Century, it cut trenches more than 40 feet deep.

The futuristic facility was powered by a portable 1,500 kilowatt nuclear reactor constructed in New York. Weighing 472 tons, this first-of-its-kind prefabricated nuclear plant was broken down into 27 large parts and flown to the Greenland coast. There the packaged components were sledded in 100 miles to Camp Century (thus the name). Using just 100 pounds of atomic fuel, the $6 million nuclear-powered unit displaced the 555,000 gallons of diesel fuel required to run the camp every year. Despite serious issues with excessive radiation and a multitude of problems in the steam generator system, engineers eventually overcame most obstacles.

Once trenches were cut, corrugated sheet metal arches were fit into place and then covered with freshly milled snow. After a matter of hours, the “snowcrete” roof became rock-hard and the panels were removed and used elsewhere.

The origin of Camp Century had its roots in the late 1940s during the American-Russian Cold War, when the U. S. government decided to establish strategic, manned installations in the world’s Polar Regions. The shortest distance between Washington, D.C. and Moscow is across the Arctic Circle, and Greenland was considered a favorable location for an early warning defense system against incoming Soviet missiles.

The men who lived and worked at Camp Century proudly called themselves “Ice Worms.” Two Greenland Ice Worms were former staff members from the Central Sierra Snow Lab (CSSL) near Donner Pass; scientists Dr. Robert Gerdel and B. Lyle Hansen. This “City under Ice” may conjure visions of the villain’s cavernous ice palace in the James Bond thriller “Die another Day,” but Camp Century was the real deal, where the extraction of glacial ice cores to study prehistoric climate change (paleoclimatology) got its start.

Dr. Robert Gerdel stands in the Camp Century tunnel system, circa 1958, where the science of paleoclimatology was greatly advanced.

Based on their expertise in snow science, it’s no surprise that Dr. Gerdel and Hansen both found themselves working at Camp Century. As lead research physicist in hydrology with the U.S. Weather Bureau during the 1940s, Gerdel had established the CSSL at Soda Springs, California, as well as two other national snow labs in Oregon and Montana. B. Lyle Hansen, a brilliant engineer and physicist, arrived at the CSSL in 1950 to replace Gerdel who was being reassigned.

Dr. Gerdel’s early efforts improve our scientific understanding of the complexities of the vital Sierra snowpack laid the groundwork for a water management system that helped nourish and sustain the growth of California into an economic giant. At Camp Century Gerdel and Hansen would meet again to play an integral part in the advancement of paleoclimatology being conducted there.

Camp Century housed a complex of barracks and laboratory buildings in four different levels of ice tunnels, and accomodated up to 250 persons. As a multipurpose lab, the camp supported nearly 100 research projects over a two-year time span. 

Stay tuned for Part Two.