Napa River rising to flood stage

ST. HELENA, Calif. (KGO) -- The Napa River is continuing to rise and is expected to go over flood stage overnight.

Waterlogged driveways made passage to some wineries a difficult if not impossible task.

RELATED: Evacuations ordered for residents near Russian River in Sonoma County

There are flooded vineyards and flooded road crossings all across Napa Valley.

Oakville Grade Road between the Silverado Trail and the Napa River is closed for high water but that didn't stop drivers from barreling through anyway, taking a risk that can prove dangerous.

Rick Thomasser is the operations manager for Napa County flood. He said "There are a few homes near St. Helena that may see some flooding in their yards, things like that. But nothing really catastrophic."

RELATED: Several drivers rescued from flooded roadways in Sonoma County

Lots of water flowed down the streets of St Helena Tuesday afternoon as tourists popped around with big umbrellas. There's good news for downtown Napa, where a 2015 bypass for fast flowing Napa River waters is working just as it was designed to do.

The bypass diverts some of the river water from critical areas where it would flood the downtown in the past and is regarded by the city as a big success.

Dennis Miller, district engineer for Napa County flood, said, "With the bypass in operation, we avoid flooding in the city of Napa and that's exactly what we wanted to do. It started flowing this morning so it's doing its job. It's all good."

The river is expected to crest after midnight above the 25 foot flood stage. It could rise to potentially 27.5 feet by dawn Wednesday. Evacuations are not expected but there will be lots of localized flooding.

Watch the latest AccuWeather forecast and take a look at recent weather stories and videos.