In a presentation describing disaster scenarios for Malibu, experts say Malibu area and Topanga are ripe for a large fire. Localized tsunami probabilities are being evaluated by the Southern California Earthquake Center.
By Hans Laetz / Special to The Malibu Times
Wildfires that sweep from Simi Valley to the ocean in half a day. Some 35 years worth of accumulated brush and fuel ready to ignite Trancas Canyon. Tsunamis that wash out City Hall. Landslides cutting Pacific Coast Highway at any moment.
Those were the all too possible disaster scenarios painted by a panel of experts last week, when Malibu Coastal Vision hosted a seminar on the probability of the next round of catastrophes hitting the Malibu coastal area.
Perhaps the most chilling predictions for this year came from Los Angeles County fire officials, who said their research shows that a major Santa Monica Mountains wildfire has occurred every time more than 20 inches of rain falls in the preceding winter. More than 40 inches of rain fell this year at some local measuring stations.
“We’ve had a researcher looking at the historic records going back 80-90 years,” said Battalion Chief Mike Sandeman. “Without exception, every year that we’ve had a heavy rain … we’ve had a major Santa Ana-fueled fire.”
Sandeman also noted that the Malibu area has experienced a 4,000-acre or larger fire every five years since at least 1935. The last local fire of that size was the Calabasas fire, which blazed from the 101 Freeway to Latigo Beach in 10 hours on a windy day in 1996.
Fire researcher James Woods said the entire mountain range is liable to burn, but that the most frequent fire danger is along the coast from Point Dume east to Topanga Canyon. That swath of Malibu is the exhaust vent of a historic fire chimney that has seen numerous Santa Ana winds-fueled fires roar all the way to the Pacific from ignition points as far away as Newhall.
Woods, a California State University Long Beach geography professor, said the largest Santa Ana conflagrations are too wide to fight as they cross Mulholland Highway.
“When you have a fire start in this area, you get such a large fire corridor that they just spread wide,” he said.
“The fires that start north of the 101 Freeway can jump so quickly that by the time they hit the mountains, they are too broad and too fast to stop,” he continued. “There were 300 homes lost in 1993, that could easily come again.”
Woods has entered historic wildfire maps into a computerized database that shows some areas have a greater tendency to burn more often than others. One grassy bluff near Corral Canyon, in fact, has burned nine times since 1935. Other areas may be more at risk for fire now because they have not burned as often, Woods noted.
But his maps show a definite pattern of more frequent, large fires that move south on Santa Ana winds from the hills above Simi Valley. Crossing over the 101 Freeway in Calabasas, these fires generally burn down to Pacific Coast Highway in the swath west of Topanga Canyon and east of Kanan Dume Road.
That leaves a great deal of accumulated fuel to the west, where the hills above Malibu Park and Trancas Canyon have not burned since 1978, Woods said. The Pacific fire that burned along Pacific Coast Highway west of Trancas two years ago came “after we had gotten one inch of rain. If not for that rainfall, we would have lost 50 homes there; as it is we lost one,” Sandeman said.
On the eastern side of the frequent fire corridor lies Topanga Canyon, which Sandeman called the biggest potential fire catastrophe in the area.
“Topanga Canyon has a serious fire interface problem,” he said, noting the dense tree cover and numerous homes on steep hillsides with winding roads. “It’s a disaster that is just waiting to happen. And it will happen.”
Fire was not the only disaster discussed at the meeting. Malibu emergency services director Brad Davis told the group that localized tsunami probabilities are being evaluated by the Southern California Earthquake Center. Los Angeles County has asked the center to evaluate the danger for tsunamis, which is thought to be low, and for seiche (pronounced sigh-shhh) waves, which might be higher than anticipated.
Seiche waves (waves that oscillates resonantly) are caused by local earthquakes triggering undersea landslides.
SCEC researchers are looking at the possibility of an earthquake on the medium sized faults at the Palos Verde peninsula or Catalina Island causing a seiche wave that could suddenly inundate Malibu with very scant notice.
Davis noted that evacuation routes into the hills might be posted once the study is finished.