Why is Southern California burning in December? A climate scientist’s answer


Southern California may get the Santa Ana winds every year, but — according to recorded history — they’ve never been like this.

With relative humidities in the single digits along the coastal mountains, where a series of fires has scorched thousands of acres and destroyed more than 100 homes, the air is the driest it’s been here in recorded history, said UCLA climate scientist Daniel Swain.

“The [relative] humidities right now along the coast are much drier than what you’d normally see in the interior desert in the summertime,” Swain said. “Once you get down to 1% or 2%, you’re down almost as low as is physically possible.”

It’s just a pile-on of bad news for firefighters and residents on the edge of the urban-wildland interface who are the first to get hit by wind-driven brush fires.

A layer of bone-dry, dead or dying vegetation has blanketed the Southern California landscape after a historically wet winter sprouted up green shoots that were summarily killed by the hottest summer on record. Then came October and November, which also were the hottest on record for Southern California, Swain said…

Read more : LA Times, 07.12.2017