early on, the napa valley demonstrated leadership in producing quality wine. at the exposition universelle in paris in 1889, napa valley wines won 20 of the 34 medals or awards (including four gold medals) won by california entries. this was the high point that was followed by 40 years of natural and human-caused disasters. severe frosts, the outbreak of the phylloxera louse which destroyed "vitis vinifera" vines, an economic depression, the san francisco earthquake that destroyed an estimated of wine in storage, and the disaster of national prohibition from 1920 through 1933.