CLAYTON (KPIX) — Sunday’s surprising thunderstorm lit up the foothills beneath Mount Diablo in Contra Costa County and with it came the fires.

Lightning strikes in the area began about 3 a.m. Sunday and continued for hours — each strike followed by rumbling thunder that lasted 10-15 seconds and shook the houses below. Susanna Thompson and Tony Adams were directly under the storm in their home on Marsh Creek Road. They were close enough to actually hear and feel the lightning bolts.

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“Sort of like a Tesla coil like you see in the movies,” Tony Adams said. “You hear the ‘Zzzzz” as it’s coming through and then the hair on your arm stands up because the whole air is energized.”

Lightning Strikes Coast Range in Contra Costa County

Lightning strikes hills near Mount Diablo in Contra Costa County. (CBS)

Around 6 a.m. strikes began reaching the ground. One started a fire on a ridge above Briones Valley Rd. Soon, other fires began including one along Marsh Creek Rd and another on a nearby hill. But the biggest one started about 8 a.m. and Susanna Thompson called it in.

“We were watching strikes all around and you watch and go, ‘did it go all the way to the ground? Is it actually going to start a fire or is it just an airstrike?’ … So you wait and see if there’s going to be smoke and there was — in two places,” Thompson said.

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The “Round Fire” is in the Round Valley Regional Preserve east of Mount Diablo. It is rugged terrain so firefighters are working with 4-wheel drive vehicles and air tankers are dropping fire retardant.

Steve Aubert/PIO, East Contra Costa Fire Protection District

“This one in the park is actually really remote,” explained Steve Aubert, information officer with the East Contra Costa Fire Protection District. “It’s an open preserve so there’s no structures really up inside there.”

They’d like to keep it confined but, as the day wore on, the fire’s intensity seemed to grow. Susanna is keeping an eye on it from her home and says it is actually the second time this year that lightning has sparked a blaze in the preserve which, she says, disproves the old adage.

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“So, twice in a summer now on the same parcel … Lightning did strike twice.”