A line of strong storms associated with a low pressure system crossing California and a cold front moving down the coast on Wednesday afternoon produced two tornadoes in San Luis Obispo County just before 16:00. This area is located on the coast about 160 miles (260 km) west of Los Angeles.
After a damage survey conducted by the National Weather Service office in Oxnard, California, meteorologists determined both tornadoes achieved wind speeds of 95 mph (150 km/h) to be classified as EF-1. In addition to being the first tornadoes in San Luis Obispo County since 2004, they were the strongest recorded since before 1950.
The first tornado touched down at 15:41 and tracked 5 miles (8 km) in a rural area between Los Osos and San Luis Obispo, remaining on the ground for about six minutes. The path was generally along Los Osos Valley Road where intermittent damage was caused.
According to a National Weather Service report, the strongest damage “consisted of several snapped and downed power poles, with sections of a roof torn off a greenhouse.” The power utility had placed temporary power poles in affected spots by the time surveyors from the Oxnard office arrived. The tornado dissipated before reaching San Luis Obispo.
The second tornado produced substantial damage as, unlike the Los Osos tornado, it tracked through the coastal community of Grover Beach, crossed US 101, and passed through parts of Arroyo Grande. It was only on the ground for two minutes, passing through about 1 mile (1.6 km) of neighborhoods and commercial areas.
National Weather Service surveyors note that multiple trees were “uprooted and toppled … some falling into and damaging vehicles and powerlines.” Several businesses took damage and the wind “buckled metal garages.” While this tornado did not last as long or track as far as the Los Osos one about ten minutes before it, it caused more damage since it tracked through a more populated area.
Tornadoes are rare in California but are not unheard of. The state averages nine tornadoes per year, compared to three each in both Washington and Oregon. Part of this higher number results simply from the state being much larger but they are slightly more common in parts of California than in the Pacific Northwest.
It is notable that both of these tornadoes tracked through fairly mountainous regions. A common misconception is that hills and mountains can protect people from tornadoes. While it is true that massive edifices (like Mount Shasta or Mount Rainier) may alter the wind flow pattern to impact tornado development, in most cases terrain does not pose a significant problem for tornadoes.
In 1999, a tornado tracked through downtown Salt Lake City before moving into higher terrain to the northeast. More notably in 1987 a F4 tornado was observed in the Teton-Yellowstone area of Wyoming and remains the strongest tornado recorded in that state.
Returning to California, a tornado was recorded above 12,000 feet (3,600 m) elevation in Sequoia National Park. While being a fairly mountainous region, San Luis Obispo County does not reach the same lofty altitude as the Sierra Nevada on the eastern side of the state.
The featured image is radar reflectivity and velocity at 15:58 PST February 7, 2024 showing rotation from the tornado in Grover Beach and is from RadarOmega. The full report from the National Weather Service can be read at this link.
