A National Weather Service tornado warning for far East County expired at 2:07 p.m. Saturday with no immediate reports of any funnel clouds touching down, although locals got an eyeful.
A severe thunderstorm and reports from weather spotters of a funnel cloud near Brentwood triggered the warning, which lasted about 40 minutes.
John Fink of Brentwood was on Marsh Creek Road near Sellers Avenue when he spotted a huge wall cloud, which dumped so much hail and heavy rain traffic was forced to stop. As he snapped pictures of the clouds, he spotted a funnel cloud.
"I had to look at it two or three times while thinking am I really seeing what I'm seeing?" he said. "It crossed the road right in front of me. I was scared to death. It was crazy."
Fink said he did not see the twister reach the ground.
"It came close, but it didn't touch down," he said. He added that in addition to sending the pictures to the Press, he had sent them to KTVU, which resulted in a similar request from CNN a few minutes later.
Discovery Bay resident Danielle Cushman was also taking pictures.
"It was amazing. They went right over my house off of Preston and Newbury," Cushman said in an e-mail to the Press. "I have lived here 13 years and only known of a tornado to hit Contra Costa one other time, in Brentwood. It hit Perez Nursery pretty hard. Today I must have see a dozen clouds try to form. The pictures do not do it justice. To see them form and dissipate and then form again was so cool and interesting."
Torrential rains temporarily flooded roads in the Byron area, and hail accumulated on Vasco Road near Camino Diablo. No major accidents were reported, although a few vehicles spun out on the slick road, according to reports.
Residents were told to seek shelter from the storm through an emergency broadcast alert on TV and radio, but many locals instead took to the roads, their eyes on the sky looking for a twister. In numerous places near Discovery Bay and in Byron motorists pulled over to photograph bright rainbows as the thunderstorm passed.
The warning was lifted when Doppler radar indicated the storm cell had weakened to the point it was unlikely to produce a tornado.