UPDATE: 12-2-11 7:45AM (PST) A State of Emergency was declared Thursday night for the Los Angeles County. Trees and debris are blocking roads and 250,000 are without electricity. More storm warnings for today and into Friday night.
UPDATE: 12-1-11 9:00PM (PST) Police and Fire agencies are urging everyone to stay inside tonight as a new storm is about to hit Southern California during the night. Thousands are without electrical power, and it could be two days before it can be restored.
One of the strongest Santa Ana Storms in years brought gale force winds of up to 80 miles an hour to Southern California toppling trees, bringing down power lines today leaving 300,000 customers without power, according to Reuters.
A power outage at Los Angeles International Airport forced nearly two dozen inbound commercial flights to be diverted to other airports, and flight delays lingered after electricity was restored at about 8 a.m. local time, LAX spokeswoman Nancy Castles told Reuters.
This strong storm bringing damaging winds to Southern California and potentially damaging easterly winds are impacting the southwestern U.S. and are expected to continue through at least Friday. This is forecast to be the strongest easterly wind event in the past several years.
Wind gusts in excess of 140 mph have been recorded along the Sierra Crest. Santa Ana wind gusts as high as 80 mph are anticipated in southern California today, including higher-elevation areas near Los Angeles.
Dry conditions and high winds have also created a significant fire threat in southern California putting the state on alert, according the National Weather Service.
Where did the name Santa Ana Winds Originate?
Bertram Moore of the San Diego Historical Society gives a history of what has become a yearly event called The Santa Ana Winds.
The conditions to create the Santa Ana Winds begin with heavy north and northeasterly winds that are strong, blustery, and very dry. They originate in the upper atmosphere over the Sierra Nevada Mountains gathering momentum as they drop down to warm valleys and desert areas. In these areas they rise to higher altitudes as hot air is sucked in to create more wind.
The trajectory of the winds begins in the valleys of Southern California in the vicinity of Tehachapi and San Gorgonio Mountains where they dip into the canyons north and east of Santa Ana and sweep with ever gathering force down the valleys to the sea.
In the February 1933 issue of the United States Naval Institute Proceedings, Lt. Comdr. 0. H. Holtman recalled that, in the early days of Spanish exploration, it was the custom to name places and occurrences for the saint on whose day the discovery or event took place.
He mentions several storm events of hurricane force so named in the logs of early navigators. He then expresses the belief that the first Santa Ana during Spanish times must have been experienced on July 26th, Saint Anne's day, and was named for her. This seems doubtful for two reasons. The first is that the first Santa Ana would not have been an important enough event to rate a name. The second is that early records of the missions and expeditions do not mention these winds by name, although attention was paid to weather conditions.
Further research reveals a more likely derivation of the name Santa Ana Winds.
The evidence indicated that the winds were named for the locality in which the old-timers thought they originated, the Santa Ana Canyon.
Other articles are to be found written by long time residents in the valley, most of whom were positive that the name came from the locality.
There is a letter on file at the Serra Museum written by the late Ann Guern, an authority on old Spanish. In it she states that her mother, Mrs. Alice Woodbury, lived in Santa Ana from childhood. Mrs. Woodbury reported that the members of the old Spanish families in those days (she had friends among the Verdugo, Sanchez, and Figueroa families) always spoke of the Santa Anas as deriving their name from the valley, and the canyon where they were strongest.
Mr. Moore concludes, “From the facts quoted, as well as others which space does not permit mentioning, it appears that the name was given to these warm winds by early California settlers because of their supposed point of origin, the Santa Ana Canyon.”
With advanced weather science, we now know the winds actually originate in the Sierra Nevada Mountains; still, knowing how they were named gives a point of reference for identifying when they were first recognized as an extreme weather event.
Santa Anas can cause a great deal of damage. The fast, hot winds cause vegetation to dry out, increasing the danger of wildfire. Once the fires start, the winds fan the flames and hasten their spread. The winds create turbulence and establish vertical wind shear (in which winds exhibit substantial change in speed and/or direction with height), both posing aviation hazards. The winds tend to make for choppy surf conditions in the Southern California Bight, and often batter the north coast of Santa Catalina Island, including Avalon cove and the island's airport.
San Diego Historical society