A small tornado in Santa Cruz County near Watsonville on Saturday lasted only three minutes but knocked down walls of some greenhouses and uprooted trees in its path, a spokesman for the National Weather Service said.
The tornado started as a waterspout on the surface of Monterey Bay at 6:59 a.m., crossed over Sunset State Beach and grew to 20 yards wide with winds reaching 75 mph as it swept east to inland areas, said Logan Johnson, a weather service spokesman in Monterey.
The swirling winds crossed over a large farm, sent fiberglass and plastic sheeting flying off of the walls of some greenhouses and caused the metal support structure of one to cave in and damage crops growing inside, Johnson said.
The twister also blew out fiberglass windows in two other greenhouses and propelled debris into a field 30 to 50 yards from the greenhouses, Johnson said.
The wind sent agricultural cloth in the air, wrapping it around a utility pole, and uprooted several trees on San Andreas Road before ending at 7:02 a.m. just over a mile from where the tornado started, Johnson said.
The tornado, which took place about a mile south of the private Monterey Bay Academy Airport, came from the major storm front that hit the Bay Area last weekend, Johnson said.
The 20-yard width of the whirlwind was "pretty small," Johnson said. "The largest and strongest tornados can be one quarter to a half mile wide."
Tornadoes in the San Francisco Bay Area are fairly rare, but not without precedent, the most recent one occurring up north in Santa Rosa in Sonoma County in March 2011, Johnson said.
The weather service has recorded seven tornadoes in Bay Area counties over the last decade, Johnson said.
Kitayama Brothers Watsonville, at 481 San Andreas Road, the farm in the tornado's path, grows flowers in its greenhouses, including snapdragons, gerbera daisies and hydrangeas, according to Carolyn Do, branch manager of the firm's San Jose office.