The Howell Mountain AVA is an American Viticultural Area

American Viticultural Area

An American Viticultural Area is a designated wine grape-growing region in the United States distinguishable by geographic features, with boundaries defined by the Alcohol and Tobacco Tax and Trade Bureau , United States Department of the Treasury....

 located within Napa Valley AVA

Napa Valley AVA

Napa Valley AVA is an American Viticultural Area located in Napa County, California, United States. Napa Valley is considered one of the top wine regions in the United States...

. Howell Mountain is located in the Vaca Mountains on the northeast side of Napa Valley around the town of Angwin

Angwin, California

Angwin is a census-designated place in Napa County, United States. California. It is part of the northern San Francisco Bay Area. The population was 3,051 at the 2010 census. Its area code is 707. Its two zip codes are 94508 and 94576. It is in the Pacific time zone.The town was named in 1874 for...

, and overlooks the town of St. Helena

St. Helena, California

St. Helena is a city in Napa County, California, United States. It is part of the northern San Francisco Bay Area. The population was 5,814 at the 2010 census....

, California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

.

Designated an AVA in 1983, Howell Mountain was the first sub-appellation

Appellation

An appellation is a legally defined and protected geographical indication used to identify where the grapes for a wine were grown; other types of food often have appellations as well...

 within Napa Valley AVA. Most vineyards in the Howell Mountain AVA are planted between 1400 feet (426.7 m) and 2200 feet (670.6 m) above sea level

Sea level

Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...

, well above the elevations in Napa Valley that are most affected by the cool fog

Fog

Fog is a collection of water droplets or ice crystals suspended in the air at or near the Earth's surface. While fog is a type of stratus cloud, the term "fog" is typically distinguished from the more generic term "cloud" in that fog is low-lying, and the moisture in the fog is often generated...

 and wind

Wind

Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...

s from San Pablo Bay

San Pablo Bay

San Pablo Bay is a tidal estuary that forms the northern extension of San Francisco Bay in northern California in the United States. Most of the Bay is shallow; however, there is a deep water channel approximately in mid bay, which allows access to Sacramento, Stockton, Benicia, Martinez, and...

. The mountain does get cool breezes directly from the Pacific Ocean

Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

, and the relatively high elevations result in a cooler climate than on the valley floor. The soil in the appellation is volcanic

Volcano

2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...

with excellent drainage.

External links

• Howell Mountain Vintners & Growers Association Retrieved Nov. 5, 2010.