1977 sandstorm: Get a wind of this story
Published: Sunday, May. 09, 2010
Cliff Trotter and Don Weeks, both of Nipomo, came by my office the other day and had a fascinating weather story to tell.
Cliff was the engineer-manager of the Arvin-Edison Water Storage District in Kern County on Dec. 20, 1977, when a terrible windstorm struck that part of the state and caused a great amount of damage.
That year, the Eastern Pacific high was entrenched off the California coastline and kept the storm track far to the north.
This prevented all but a few weather systems from penetrating into California.
The most notable was Hurricane Doreen, which tracked northwestward along Mexico's Baja Peninsula, came onshore as a tropical depression over Orange County and produced heavy rain and floods in parts of Southern California.
Otherwise, the position of the Eastern Pacific high produced one of the worst two-year droughts in California history, from 1975 through 1977.
The San Joaquin Valley was declared a disaster area. Its soils were even more parched than normal. The snowpack measurements performed on April 1, 1977 indicated the lowest water content in 47 years.
As the winter of 1977 approached, the air over the high deserts of the western United States cooled and became dense.
On Dec. 20, an exceptionally strong area of high pressure moved southward over the Great Basin.
At the same time, an intense low-pressure system and its associated cold front approached the coast of Northern California. This condition produced a very steep pressure gradient through the Central Valley.
The air flowed in a clockwise direction around the high pressure system, forcing cool and dry desert air down the Tehachapi mountain canyons toward the southern San Joaquin Valley.
As gravity pulled the air mass toward the valley floor, it funneled through the mountain passes and canyons, producing hurricane-force east-southeasterly winds.
To make matters worse, as this air mass descended, it was compressed, and its temperature increased. As air heats, its relative humidity decreases, so the air became very dry.
Some of the strongest winds ever recorded in California history slammed into the southern San Joaquin Valley that day and, combined with the extraordinarily dry soil, produced a fearsome dust and sand storm.
Sustained winds reached 125 mph and caused extensive damage to buildings and fertile farmland. The U.S. Geological Survey estimated that wind gusts reached 192 mph at Arvin!
Trotter said, "Vehicles that were left outside during that windstorm were literally sandblasted."
The winds carried tremendous amounts of soil that filled in many of the water canals that criss-crossed that part of the valley. It took weeks of work by heavy equipment operators to clear some those canals.
Not surprisingly, large volumes of dust were carried northward through the San Joaquin and Sacramento valleys toward the Oregon border. Dust from this storm obscured the sun as far north as Colusa County.
An outbreak of Valley fever followed as spores traveled into Sacramento and Redding. Months later, hydrographers found a layer of dust embedded in the snowpack in the Mount Shasta area that was probably from this event.
Thankfully, El Niño made its appearance that winter, and the storm track shifted southward, producing above-normal rainfall and ending the severe California drought.
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