The Chivela Pass is a narrow

mountain pass A mountain pass is a navigable route through a mountain range or over a ridge. Since mountain ranges can present formidable barriers to travel, passes have played a key role in trade, war, and both Human migration, human and animal migration t ...

in the Sierra Madre Mountains that funnels cooler, drier air from the North American continent, through southern

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

, into the

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...

. These northeasterly winds, specifically the Tehuano wind, blows periodically across the

Isthmus of Tehuantepec The Isthmus of Tehuantepec () is an isthmus in Mexico. It represents the shortest distance between the Gulf of Mexico and the Pacific Ocean. Before the opening of the Panama Canal, it was a major overland transport route known simply as the T ...

in southern Mexico, and offshore over hundreds of miles of the Pacific Ocean. The wind activity forces the upwelling of colder subsurface waters. This strong upwelling brings nutrients from the subsurface layers of the ocean, thereby enhancing the fertility of the offshore waters. This results in strong plankton growth which in turn supports a more bountiful fishery in the region. In extreme circumstances during the winter, truly cold, dense air occasionally flows from the

Bay of Campeche The Bay of Campeche (), or Campeche Sound, is a bight in the southern area of the Gulf of Mexico, forming the north side of the Isthmus of Tehuantepec. It is surrounded on three sides by the Mexican states of Campeche, Tabasco and Veracruz. The ...

in the

Gulf of Mexico The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...

through the Chivela Pass into the

Gulf of Tehuantepec The Gulf of Tehuantepec () is a large body of water on the Pacific coast of the Isthmus of Tehuantepec, southeastern Mexico, at . Many (but not all) Pacific hurricanes form in or near this body of water. A strong, gale-force wind called the T ...

on the Pacific side. These winds can be strong enough to sandblast paint off ships in near-coastal waters.

Notes

External links

The Gulf of Tehuantepec Hurricane Force Wind Event of 30-31 March 2003The Structure and Evolution of Gap Outflow over the Gulf of Tehuantepec, Mexico
Atmospheric dynamics Mountain passes of Mexico Landforms of Oaxaca Rail mountain passes of Mexico {{Oaxaca-geo-stub