Winds flow from high pressure areas to low pressure areas. Santa Anas form when there is high pressure on the Great Basin, located in Nevada and parts of Utah, and low pressure on Southern California. The winds come from the desert, but that's not why they're hot.
Santa Ana
winds are strong and extremely dry winds that originate inland and affect the coast of Southern California and northern Baja California.They originate from cold, dry air masses at high pressure in the Great Basin. These winds are caused by high pressure over the Great Basin with low pressure off the coast. Winds flow from high pressure to low pressure, and the stronger the gradient (or the pressure difference between the two), the stronger those winds can be. As the winds approach sea level, they accelerate, dry out and warm the air.
NWS All NOAA Santa Ana winds occur when air from a high-pressure region over the dry and desert region of the southwestern U.S. UU. It flows west to the low pressure off the coast of California. This creates dry winds that flow from east to west through the mountainous passages of Southern California.
These winds are most common during the coldest months of the year, and occur from September to May. Santa Ana winds generally feel warm (or even hot) because as fresh desert air moves up the mountainside, it compresses, causing the air temperature to rise. These strong winds can cause significant damage to property. They also increase the risk of wildfires due to dry winds and the speed at which they can spread a flame across the landscape.
In short, they are caused by high pressure over the Mohave Desert and the Great Basin, along with overall low pressure in Southern California. Hot, dry, high-pressure air seeks to go to low-pressure areas. Normally, this would be a fairly quiet exchange, but because of all the mountains that surround Southern California, air movements are channeled through the three main mountain passes: Soledad, Cajón and San Gorgonio. This channeling action creates huge wind currents that result in those fierce and dry gusts that we know very well in our area.
Santa Ana winds have been recognized and reported in English records as a meteorological phenomenon in Southern California since at least the mid-19th century. My research has suggested that the Santa Ana Canyon theory for the name of the wind is the most reasonable explanation. Because high-pressure areas generally migrate eastward, shifting the pressure gradient in Southern California to the northeast, it is common for evening wind episodes to precede those in Santa Ana by one or two days. The combination of hot, dry and windy contributes to a number of changes in climate, including record temperatures and, most notably, fire-hazardous weather conditions.
Since then, some people have continued to use the term “santana” for winds, although historically they are (and have been) the Santa Ana winds. Winds often hit Southern California during the driest part of the year, providing a metaphorical bit of gasoline to the area's already fire-ready tinder. It was one of those hot and dry Santa Anas that goes down the mountain passes and curls your hair and makes your nerves jump and your skin itches. The most widely accepted explanation for the name Santa Ana winds is that it is derived from the Santa Ana Canyon in Orange County, one of many places where the winds blow intensely.
However, a true Santa Ana fog is rare, because it requires conditions that lead to a rapid reform of the marine layer, in addition to a rapid and strong reversal of wind gradients from sea to land winds. I get a lot of emails from people who insist that the winds of Santa Ana are actually the winds of Santana, and Santana supposedly represents the devil in Spanish or in an Indian language. As a weather phenomenon that is unique to Southern California, Santa Anas has long been associated with a certain sensation. The Santa Ana winds are known for the warm and dry weather they bring in autumn (often the hottest of the year), but they can also arise at other times of the year.
If the Santa Anas are strong, the usual daytime sea breeze may not rise or weaken later in the day because strong desert winds on the high seas oppose the sea breeze on the coast. In Santa Ana's strongest events, damaging gusts of up to 70 mph will be more widespread, and windiest canyons, such as Fremont Canyon in Orange County, will have gusts of 100 mph. To live with Santa Ana is to accept, consciously or unconsciously, a deeply mechanistic view of human behavior. .
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