[caption id="attachment_97391" align="aligncenter" width="500"] The Aug. 24 south Napa Valley quake toppled barrels and cases of wine at The Hess Collection's American Canyon warehouse. (credit: Robert Russo, The Hess Collection)[/caption]

NAPA -- The Aug. 24 south Napa earthquake caused more than $80 million in damages and losses to wineries in the county, according to a wine-focused bank estimate presented Tuesday to Napa County officials.

Napa Valley's wine business incurred $70 million to $100 million in damages, but likely about $80.3 million, per figures tallied by Silicon Valley Bank's Premium Wine Division, which the Napa County Board of Supervisors and trade group Napa Valley Vintners commissioned to study the impact of the 6.0-magnitude quake.

But the bill may climb higher, as damage and losses are uncovered and contractors and engineers fully assess what happened, according to Rob McMillan, bank executive vice president, division founder and author of the report.

"We are all working from damage estimates from winemakers and winery owners, and they aren't contractors," he said.

The $80.3 million figure includes damage to winery buildings, infrastructure such as wastewater ponds and private bridges, winemaking equipment, vineyard irrigation systems; losses of wine aging in tanks or barrels; barrels and tanks themselves; wine ready for bottling; packaging; and tasting rooms and hospitality facilities. Also included are costs of cleanup and removal of debris and waste, downtime for operations and lost direct-sales revenue.

Sixty percent of Napa County wineries sustained damage, and up to a quarter had moderate to severe damage, the report said. Losses per operation ranged from $50,000 to $8 million in the most devastating circumstance.

Most of the damage was concentrated in the southern and western areas of the county, particularly inside Napa, on the Napa County side of Los Carneros appellation and the Mount Veeder, Yountville and Oak Knoll winegrowing regions, the bank found.

However, wine distribution, shipping and logistics warehouses in the Napa and American Canyon industrial zone, which is near the quake epicenter, had several million dollars in damage, the report said. Yet the impact was significantly less than expected, likely because of modern building codes and inventory-protection strategies, the document concluded.

The report was presented at the county board's meeting as part of documentation being compiled to support Governor Brown's Sept. 2 request for President Obama to declare a major disaster for the area, opening the possibility for federal assistance programs such as low-interest business loans.

The county called in Mr. McMillan to complete a quake-impact analysis based on the bank's database of winery financial information, the bank's post-quake assessments, more than 100 reports of winery damage submitted to the county and his interviews with affected wineries.

This latest estimate pushes the damage figure for the quake to more than $400 million, according to a county spokesman.