Students and faculty all over campus have been hoping for more rain, but the probability of a wet season continues to drop. Scientists predict that strong rain will continue throughout the winter, because of what many know as an El Niño year. Although this is a promising outlook, El Nino is often misinterpreted.
An El Niño year is caused by the the shifting of warm surface temperatures from Japan and Indonesia to the west coast of California and Mexico.
Local weather expert and Thacher chemistry teacher, Dr. Chris Vyhnal explains that, “the precipitation follows that warm water. If you have a warmer surface temperatures in the ocean, then you get more evaporation on the ocean, and that precipitates out as thunderstorms.”
This pattern occurs about every three to five years, and lasts from 9 to 12 months per season. If ocean surface temperatures rise a half degree Celsius over normal surface temperatures for three consecutive months it is officially named an El Niño season.
Although strong El Niño seasons can bring lots of rain, there are accounts of a normal El Niño bringing some of the driest years as well. Contrary to popular belief, an El Niño season does not necessarily mean that California will get above average rainfall. The driest year in Los Angeles’ recorded history, 2006-2007, occurred during a weak but still official El Niño year. Looking at the past, it is unwise for Californians to rely on El Niño to relieve the state’s extreme drought.
The chances of an El Niño season was 90% in June, but at the beginning of December it had dropped to 65% and has stayed there since. Even if there is not a full El Niño, scientists know that it will not be a dry season either, called La Niña.
La Niña is the opposite of El Niño, with unusually dry weather in the west and heavy rains in the east. The last time this occurred was during the long two year period between 2010 and 2012. Some scientist have blamed this for the continued drought that has plagued California.
This historic drought has put California is desperate need of the rain. But other than the obvious benefit of replenishing California’s water supplies, there are many other positive and negative effects to an El Niño season.
In the past years the average winter ocean water surface temperature in southern California has been 56 degrees Fahrenheit. But, recent data shows that Ventura has been 58-60° F and San Diego has been 62° F. This means that the water is at least 2 degrees warmer than average, which is very good sign for an El Niño year.
The additional positive effect of the warmer waters is the more welcoming feel for those who head to the beach.
Director of Admissions, Bill McMahon, noticed the warmer waters while surfing. “You saw people out late fall, with no wetsuit.”
Yet, as the surface temperature increases, there are more crop failures in South Asia and reduced fish catches in the eastern Pacific. As any wet season brings, El Nino also brings flooding and erosion throughout southern California.
Instead of the heavy dumping rainstorms, what the drought really needs is a long period of slow and steady almost misting rain like Ojai received this past weekend.
As on January 12th, NOAA updated the chances to 50%-60%. See http://www.elnino.noaa.gov