Strong winds whose direction can change by the hour, low humidity and warm temperatures will continue this week to challenge firefighters and pose a threat to those who live near the brush fires that have burned thousands of acres in Los Angeles and San Bernardino counties this weekend.
Already, the National Weather Service said, an anticipated change in the wind direction occurred on Sunday, June 16, at the Hesperia fire burning off Highway 173. The fire, which had been dying down as it burned southward away from a housing development, was now being pushed back to the north.
In northern LA County’s Gorman area, the weather service issued a red flag warning through 3 p.m. Monday for the Post fire burning off the 5 Freeway.
“What you could expect, because of the wind and humidity conditions along with the drying of the fuels, you could see rapid fire spread and extreme fire behavior,” said David Gomberg, a meteorologist in the Los Angeles/Oxnard office. “It could be very erratic.”
Now is the time for residents to prepare to evacuate because such an order could come at a moment’s notice, Gomberg said.
Winds with gusts of 45 mph to 55 mph are forecast to blow to the south and southeast through Monday night. Although the humidity is not in the single digits — it’s 15% to 25% — that’s enough to dry out the brush.
“With the strength of the wind, you don’t need that low of humidity,” Gomberg said.
Starting Tuesday morning, winds are expected to be even warmer and drier because they will come from the northeast and flow through the hot desert before reaching Southern California, Gomberg said. High temperatures for the week are expected to be in the mid-70s.
The winds were causing multiple problems at the Post fire, said Kenichi Haskett, a spokesman for the fire commanders.
Embers were being blown up to a mile away, he said.
“And it makes it more difficult for our rotary and fixed wing to make accurate and precise drops,” he said.
Fortunately, the wind direction has been consistent. Sudden changes, Haskett said, are “taking a situation that’s predictable and making it tumultuous.”
In Hesperia, forecast highs are in the high 80s, said Elizabeth Adams, a meteorologist in the weather service’s San Diego office.
The wind shifted at midday Sunday and was blowing from the southwest at 12 mph to 16 mph with gusts of 25 mph. Humidity was at 15% to 25%, Adams said. Monday’s winds could be slightly faster, she said.