A wave of weekend thunderstorms brought Portland its second-wettest day of the year Saturday. And where there's thunder, there's lightning.

As anybody sitting on a patio Friday night could attest, this weekend's bands of storms were electric. But the lightning strikes mostly stayed east of Portland. The highest concentration of lightning was in the Cascades and their foothills, says Matthew Cullen, a meteorologist with the National Weather Service's Portland office.

Cullen says towns at each end of the Columbia River Gorge, like Troutdale and Hood River, "saw quite a bit of lightning, more than we've seen in some time."

He says such thunderstorms only happen two or three times a year on the west side of the Cascades.

"It's usually a handful of days each year that we see more widespread lightning," Cullen says. "The mountains really help these storms to get going. When the upper-level winds draw these storms in from the Cascades, that's when we really see a lot of lightning. And that's what happened on Friday night and Saturday morning."

East of the Cascades, in Central Oregon, lightning storms are more common—and a time-lapse map of Oregon's lightning suggests they were far more intense than what Portlanders observed.

"They saw just prolific amounts of lightning in Bend and north to Pendleton," Cullen says.

From 8 am Saturday to 8 am Sunday, a National Weather Service contractor counted 4,789 lightning strikes in Oregon.

(Courtesy of National Weather Service, Seattle office)
(Courtesy of National Weather Service, Seattle office)

The fire departments that partner with the National Weather Service's Portland office reported several small blazes started by lightning strikes in western Oregon and Washington. But they were quickly extinguished.