At this point, it would be nearly impossible to find someone who hasn’t heard that a strong El Niño is brewing in the equatorial Pacific Ocean. For months now, extremely warm sea surface temperatures have signaled that a cyclical ENSO (El Niño Southern Oscillation) event will be impacting global weather patterns this winter. Particularly for Southern California, warnings for potential heavy rain, floods, mudslides and destructive waves have been broadcast in every form of media.
Southern Pacific snow removal crews were busy in 1983. | Courtesy Mark McLaughlin
Although El Niño events occur on a regular basis, this 2015-16 event is being rated in the strong to very strong category. Since 1950, there have only been five that have reached this level of anomalous ocean warmth: 1957-58, 1965-66, 1972-73, 1982-83 and 1997-98. All but one – 1966 – delivered above normal precipitation to the Tahoe Sierra.
“The key to a snowy winter at Lake Tahoe will require
moisture-laden atmospheric river events meeting with cold Alaskan
air over the Central and Northern Sierra.”
ENSO events occur in varying strengths and no two are alike. Only relatively recently have scientists begun to learn a lot more about its effect on the jet stream and winter storm patterns. And that is why the alarm is up for unusually stormy conditions January through March for drough-ravaged Southern California. The odds for a wetter than normal rainy season gradually decrease the further north one goes along the West Coast.
Due to the increased intensity of the subtropical jet stream and its focus on the southern tier of states this winter, drier than average conditions are anticipated in the Pacific Northwest during the next six months. Seasonal forecasts for the Tahoe Sierra tilt slightly toward wetter and warmer than normal. The key to a snowy winter at Lake Tahoe will require moisture-laden atmospheric river events meeting with cold Alaskan air over the Central and Northern Sierra.
The winters of 1983 and 1998 are the only two seasons to date that were driven by rare “very strong” El Niño conditions. Both were exceptional when it came to snowfall and precipitation in Northern California, but 1983 proved to be a monster. Nearly 67 feet of snow fell at Norden near Donner Pass that year (nearly double the average 34 feet), the sixth greatest total for that location since snowfall records began in 1879. The incessant storm activity and heavy snowfall took its toll on local residents and businesses, as well as visitors looking to ski some of the deepest powder in decades.
The 1983 season crushed the Tahoe Sierra with rapid-fire storms. Road closures and structural damage were common and frequent. It still ranks as one of the worst in California history. Severe weather that winter killed 36 people, injured 481 and caused $1.2 billion in economic losses in the Golden State. Peak snow depths at Donner Pass exceeded 17 feet; some of the deepest measured there since World War II. The impact was so devastating in California and around the world that 1983 is the year that put the previously little-known word El Niño into the lexicon of the media and popular culture.
Typically, California can expect about four or five major storms during the course of the five-month rainy season from November through March. But in 1983 potent storms came early, originated in various regions of the Pacific Ocean and persisted until early May with only short reprieves. Heavy snow buried the mountains, torrential rain lashed the lowlands and 25-foot waves frequently pounded the coast from Fort Bragg to San Diego.
In the fall of 1982, an unusually strong El Niño event in the Pacific Ocean was adding more juice to the jet stream and some climatologists warned of increased potential for a wet winter in portions of the United States. Over the winter months a persistent, deep, low-pressure system in the Gulf of Alaska combined with an intensified high-pressure dome in the central Pacific to squeeze the jet stream and effectively double the speed of the westerly flow of air across the ocean. Fast-moving storm systems embedded in the jet stream were fueled by released energy from exceptionally warm seawater as they raced toward the West Coast. Depending on your perspective, it was either a recipe for disaster or a powder hound’s ultimate fantasy.
Despite the atmospheric and oceanic signals in late 1982, most forecasters were paying little attention to the developing El Niño conditions. ENSO events are not good seasonal forecasting tools and there wasn’t much in the historical record to indicate that these irregular periodic climate changes could result in epic storms and damage on a vast scale. At that time, scientists looked toward Alaska for clues to winter weather.
As a harbinger of things to come, rare September snowfall blanketed the mountains. Twice that month, tire chains were required on Interstate 80 and other local roadways. Nearly 2 inches fell in Reno, the city’s first September snowfall since 1889 when about half an inch covered the ground. The unusually early snowfall was an ominous omen: the winter of 1889-90 is known as the Great White Ruin and considered the worst in Nevada’s history.
In late October 1982, activity picked up as a strong flow of moist, subtropical air from near Hawaii inundated the Sierra with heavy rain and high elevation snow. This atmospheric river soaked Blue Canyon on the Sierra west slope with more than 10 inches of rain, more than double its October average. The jet stream soon shifted, however, and a week later the first in a series of cold storms from the Gulf of Alaska slammed the West Coast. This relentless stream of powerful weather systems buried the Truckee-Tahoe region. Most resort operators had never seen anything like it.
To top off a snowy November, the last storm was a wild one, dumping 4 feet in downtown Truckee, which paralyzed traffic and closed schools for two days. Alpine Meadows ski area picked up 87 inches of snow that month, which got the resort off to a great start. By Dec. 1, more than 6 feet of snow covered the ground at Norden, compared to an average of 11 inches for that time of year. In many locations in the Sierra, it was the wettest fall season (September to November) on record. And, it was just the beginning.
Tahoe historian Mark McLaughlin is a nationally published author and professional speaker. His award-winning books are available at local stores or at thestormking.com. You may reach him at [email protected] Check out his blog at tahoenuggets.com or read more at TheTahoeWeekly.com