the WEATHER CORNER

A ranking of Bay Area weather extremes over the past five decades

BY JAN NULL
Special to the Mercury News

WITH everyone else compiling end-of-the-century lists, the Weather Corner will weigh in with the Top 10 Bay Area weather events of the past 50 years.  These are the events that I think had the greatest impact on the region. Listed in chronological order, they go back only to 1950 because that is the period about which I have the most knowledge.

1955 Christmas floods: Widespread flooding affected most of northern and north-central California from Dec. 19-27, 1955. More than 42 inches of rain fell in the Santa Cruz Mountains. Santa Cruz suffered its worst flood on record, with eight feet of water coursing through the downtown area. Nine people died. Much of the Santa Clara Valley and southern Alameda County were inundated when just about every stream and creek breached its levees.

Drought of 1975-77: This was the driest two-year period on record in California, characterized by bricks in toilet tanks, dead lawns, dirty cars and very strict restrictions on water use. In that two-year period, San Francisco received only 19.01 inches of rain, compared to a normal 43 inches. San Jose recorded only 14.75 inches, while 28.80 inches would be expected.

Snowstorm of 1976: Snow fell at sea level throughout the Bay Area on Feb. 5, 1976, and there hasn't been any significant snow at that low elevation in the region since. In the Santa Clara Valley, totals of an inch were typical, while 3 to 6 inches fell at higher elevations, closing many roads. The steep streets of San Francisco became impassable. Twin Peaks was buried under 3.5 inches of snow.

1982 floods, mudslides: A slow-moving weather system dumped torrential rains on the region to trigger widespread floods and mudslides Jan. 3-5, 1982. On Jan. 4, at the peak of the storm, 5 to 15 inches of rain was measured around the Bay Area. And over the three days, 25 inches fell in the Santa Cruz Mountains. The heavy rain fell on already saturated soils, triggering vast mudslides and debris flows. The worst was at Love Creek, where as many as a dozen people were killed. People often think of these as El Niņo-caused events. However, they preceded the onset of El Niņo conditions in the eastern Pacific that triggered the 1982-1983 storms.

1982-83 El Niņo storms: These storms in the winter of 1982-83 produced record seasonal rainfall at many locations throughout the Bay Area and central coast, with more than 100 inches measured at places in the mountains. San Jose got 30.25 inches, making it the second-wettest winter on record.  San Francisco measured 38.17 inches, Ben Lomond 95.60 inches and Sonoma 117.03 inches. Mining Ridge, in Monterey County's coastal mountains, recorded 173.37 inches -- more than 14 feet of rain. Statewide, 58 stations exceeded 100 inches for the season. The extended periods of heavy rain caused hundreds of mudslides, including spectacular slides in  Pacifica and the Santa Cruz Mountains.

1986 Pineapple storms: An atmospheric phenomenon called the ``pineapple connection'' can bring a stream of warm moist air from the tropics near Hawaii to California. For 10 days -- Feb. 11 to 20, 1986 -- it sent a series of warm storms with copious rainfall out of the southwest to drench California. The Russian and Napa river basins were especially hard-hit with 20 to 40 inches of rain that pushed flood levels to record heights.
Heavy rain also triggered flooding along smaller streams and creeks as far south as Santa Cruz.

Big freeze of 1990: A mass of frigid air from Canada and Alaska swept over California on Dec. 20, 1990, beginning a freeze that lasted nearly two weeks. Statewide, it caused $780 million in agricultural damage. In the Bay Area, the extended period of below-freezing nights caused extensive
damage to ornamental plants and trees. Water pipes froze, then burst when they thawed. In San Jose, the temperature dropped to its second-coldest reading on record -- a chilly 19 degrees on three separate occasions. And thermometer readings dipped below freezing on 32 days that winter.

The 1991 firestorm: On Oct. 20, 1991, afternoon temperatures were in the low 90s in the Oakland hills, and Diablo winds out of the northeast caused humidity to plummet. Fire conditions were made even more dangerous by an abundance of dead plants and trees killed in the big freeze the
previous winter. Winds gusting to 25 mph fanned the embers of a small fire thought to be extinguished into a major wildfire that raged more than 48 hours. The Oakland hills firestorm killed 25 and injured 150. It destroyed more than 4,000 dwellings and 2,000 automobiles, causing overall damage of $1.6 billion.

Floods of 1995: In January 1995, and again in March, California was hit by a double whammy of flooding. The January storms mostly affected Northern California, while the storms in March concentrated on the central part of the state. The storms caused nearly $2 billion in damage statewide, and 42 of California's 58 counties were declared disaster areas. Most Bay Area rivers flooded in January and again in March as
rainfall measured 5 to 10 inches each month. In March, the Guadalupe River flooded downtown San Jose and neighborhoods near Civic Center. The Salinas and Pajaro rivers overflowed to cut off the Monterey Peninsula.

The 1995 windstorm: On Dec. 12, 1995, some of the strongest winds ever recorded in the Bay Area smashed through, accompanied by heavy rains that caused local flooding. Winds over the higher elevations peaked at more than 100 mph, with some lowland gusts exceeding 70 mph.
Property and agricultural damage from the storm added up to about $65 million, including more than $15 million in San Francisco, where the storm devastated trees and the arboretum in Golden Gate Park. The storm knocked out power to 1.3 million Pacific Gas & Electric Co. customers. The
windstorm was estimated to be a 50-year event, which means it has a 2 percent chance of occurring any year.

Honorable mentions: Two other weather events of the past century are worth noting: the May 1998 Sunnyvale/Los Altos tornado and the 1962 Columbus Day storm.

Jan Null, founder of Golden Gate Weather Services, is a retired lead forecaster with the National Weather Service. Send questions to him c/o Weather Corner, San Jose Mercury News, 750 Ridder Park Drive, San Jose, Calif. 95190. You also telephone and fax questions at (510) 657-2246 or e-mail them to (weathercorner@ ggweather.com).