Critical conditions on Wednesday are due to the impact of moderate to locally strong Santa Ana winds combined with very low humidity, BBC forecaster Sarah Keith-Lucas said.
Winds are expected to peak again at 03:00 local time (11:00 GMT) within twelve hours, according to the local office of the National Weather Service (NWS). Gusts could reach 50 mph (80 km/h).
Winds are “lighter but still strong” compared to last week’s conditions, the NWS warned.
For this reason, areas northwest of Los Angeles — including Simi Valley and Thousand Oaks — were deemed particularly dangerous.
But conditions are forecast to improve later Thursday and Friday. Despite the change in winds, no precipitation is forecast for at least next week, added BBC forecaster Sarah Keith-Lucas. And Santa Ana winds, which have been blamed for fueling the fires, could develop again starting Sunday.
The Pasadena City Fire Chief reiterated the need for rainfall.
“There hasn’t been any real rain in southern California” for more than 250 days, Chad Augustine told BBC Radio 4’s Today programme.
On Wednesday, his firefighters will “stand watch to make sure we hold our containment lines and don’t burn any more structures,” Mr Augustine added.
