Despite drought, potential flooding is concern in Napa

The rainstorm headed to the Bay Area is greatly needed but may come with its own set of problems.

Historically, downtown Napa has been an area prone to flooding. It often happens when the Napa River is full, which is a non-issue this year.

But the storm could still bring problems, so people are preparing.

An ACE hardware in Napa has seen brisk business the last few days.

"Anything to do with water mitigation," said Ken Graham, a sales associate and resident.

Graham showed us one of the most popular items, something called Play Sand.

The pallet of 80 50-pound bags was down to about 10 in short order.

"Basically a sandbag is in porous material where play sand is wrapped in plastic that is not going to allow moisture to come in and out," said Graham.

Rick Sunny knows his next few days will be wet and dreary, so he came in to buy a tarp and other supplies after already completing his rain prep work.

"We cleaned our gutters made sure they can flow out with the leaves coming in this time of year.  We've tried to take everything that could blow away and batten it down," said Sunny.

With the Napa River at low levels due to the drought, there’s no threat of it spilling over its banks.

But the county has prepared for localized flooding.

"So, we do have storm patrols and roads crews who are patrolling over the weekend looking for possible problems. We have a lot of folks who are on standby monitoring the storm conditions," said Leah Greenbaum, a county emergency services coordinator.

With the storm expected to bring three or more inches of rain to the Napa mountains, there are many potentially vulnerable areas in the burn-scarred areas, like Deer Park.

There’s a flash flood watch in the region where a deluge could send debris flows cascading down the mountains.

"These are the areas of concern because obviously, the ground is unstable so that definitely could be impacted with these rains," said Napa County PIO, Erick Hernandez.

In some burned-out areas where the ground is particularly unstable, property has already been cleaned up and erosion mitigation work completed.

But with hundreds of acres of burned-out hillsides, there are plenty of areas where water and debris could come rushing down.

First responders from various agencies say they are prepared for whatever the storm may bring.

One welcome benefit from the impending storm, a significant reduction in what has been the biggest risk this year.

"It definitely minimizes any potential risk as far as Wildland fires," said Hernandez.

At one point Saturday afternoon, the sun briefly peered through the clouds in Napa.

Shortly thereafter, it quickly turned to drizzle, which is expected to transform into serious rain beginning Sunday.