Freak thunderstorm, lightning slammed SLO County, flooding Highway 166
A sudden late summer storm brought heavy downpours, thunderstorms and even flooded a highway in San Luis Obispo County on Thursday.
The National Weather Service issued a flash flood warning for southeastern San Luis Obispo County and a flood advisory for interior San Luis Obispo County on Thursday afternoon through 7 p.m.
The Weather Service also extended an existing flood watch for the county until 5 a.m. on Friday and warned people to stay off of mountain roads.
Thunderstorms building above San Luis Obispo County unleashed heavy rainfall near the eastern border during the afternoon and evening and left inland areas vulnerable to flash flooding, the Weather Service said.
The expected rainfall rate was 1 to 2 inches in an hour, the agency said, noting flash flooding was ongoing or expected to begin shortly and landslides were expected.
“Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations,” the Weather Service said in the flood watch.
The thunderstorm even created the potential for a funnel cloud or small tornado — though none ever appeared, the agency said.
The Weather Service also warned of hail and gusts of wind that reach 40 mph from 3:42 to 4:15 p.m. on Thursday.
By 6 p.m., Highway 166 flooded near Wasioja Road outside of Santa Maria, according to CHP’s traffic incident report page.
Caltrans set up an eastern closure of Highway 166 at New Cuyama and a western closure at mile marker 55, the CHP log said.
Meanwhile, a storm cell opened up with heavy rain in the North County as the skies darkened from the east and thunderclaps rolled in.
The National Weather Service issued a special weather statement for the area between Morro Bay and Atascadero at about 6:15 p.m., warning of pea-sized hail and winds of up to 40 mph as “torrential rainfall” slammed the area.
According to the statement, frequent cloud-to-ground lightning was occurring with the tracked storm. People were urged to seek safe shelter inside a building or vehicle.
By Friday morning, the storm had blown southeast to the border of San Luis Obispo and Santa Barbara counties and drifted into Kern County, ushering in a dry and sunny weekend for San Luis Obispo County, the Weather Service said.
This story was originally published September 19, 2024 at 4:22 PM.
