Storm unleashes hour-long lightning barrage in Fresno, causing power outages across region
The storm that brought plenty of hail and lightning Wednesday afternoon in the Fresno and Clovis areas was caused by unstable air that originated in the Bay Area, the National Weather Service in Hanford said.
Meteorologist Kevin Durfee said the storm was a “very slow moving upper level storm” that was situated off the Central California Coast and centered off San Francisco.
“The proximity to where we were at, put us in a region where the atmosphere was getting colder aloft as the day went on,” Durfee said.
Case in point: Durfee said temperatures reached to the mid-50s. When the storm arrived, temperatures dropped by 10 to 15 degrees to the lower 40s.
The NWS said there were 84 lightning strikes that hit the ground between 2:45 p.m. and 3:35 p.m. in the Fresno-Clovis area. Durfee said they will have to do research to get the total lightning strikes.
Durfee said winds gusted up to 30 mph in some places of the “more mature thunderstorms.” Pea-size to dime-size hail fell in some places.
“That is a very volatile combination during the afternoon hours in the central valley,” Durfee said. “Basically what it does, it destabilizes the atmosphere. When showers develop in that pattern, they can grow into thunderstorms. Because of how cold the air was aloft, we get a lot of these updrafts in these thunderstorms, you get these raindrops when they move up into that part of the cloud they freeze and come back down in the form of hail.
“In the very heaviest of those thunderstorms, the hail was falling so frequently for so long that it actually caused a covering of hail on the ground. We saw that in the Clovis area. We had other reports that produced an accumulation of hail on the ground. It was quite a sight to see.”
Durfee said the NWS is looking into reports of funnel clouds. The NWS detected “some” rotation with these thunderstorms aloft.
In some instances, Durfee said there was a little spin in the atmosphere going on.
“Which is what we were expecting because we had low level winds that were out of the southeast and the upper level winds were out of the west-northwest,” he said. “Even though the vertical shear was variably weak, it was enough to create a little bit of a spin in some of the thunderstorms.”
The thunderstorms turned into rain and snow showers in the mountains, with snow levels dropping to 3,500 feet. China Peak Ski Resort at Huntington Lake, with a base area at 7,000 feet, on Thursday morning reported 14 to 18 inches of new snow.
Wednesday’s rainfall total at Fresno Yosemite International Airport was three-tenths of an inch and the highest total for Fresno County was in eastern Squaw Valley at just less than 1.5 inches.
The storm left many without power for about four hours — including 20,000 PG&E customers in the Yosemite area, mostly near Mariposa and Merced, PG&E spokesman Denny Boyles said.
There also were two significant outages in the Fresno area: about 2,700 customers in an area around Ashlan and North Armstrong avenues and another 450 around the area of East Jensen and South Walnut avenues.
Boyles said most of the outages, including the Yosemite area, were restored by 8:30 p.m.
Wednesday afternoon, California Highway Patrol spokesman Mike Salas said officers were called to multiple traffic collisions related to the weather, including an overturned vehicle on its roof at Highway 41 and North Avenue.
“We want to remind drivers to reduce speed and increase following distance and wear your seat belt,” Salas said. “Make sure your windshield wipers and headlights are working.”
This story was originally published March 10, 2021 at 3:07 PM.
