Neighborhoods downslope of La Tuna Fire vulnerable to mudslides

The La Tuna Fire burned nearly 7,200 acres over the Labor Day weekend, including five houses. But hundreds more homes on the perimeter of the burn area in Los Angeles, Burbank and Glendale could be at risk if heavy winter rains trigger mudslides.
 
Two months after the fire was doused, public agencies and some private property owners are working to install barriers to keep mud and debris from damaging homes and buildings. But many homeowners don't appear to have heeded calls to prepare. 

How many homes and businesses are at risk in the burn area?

About 340 parcels are directly below areas that burned in the La Tuna Fire. It started Sept. 1, in the 10800 block of West La Tuna Canyon Road and quickly grew to one of the largest fire within Los Angeles city limits in about 50 years.

Firefighters working with aircraft dropped water and fire retardant to keep the fire from homes, but in many cases, the scorch line comes right down to residential backyards and property lines at the base of steep terrain.

That pattern is especially clear for the houses and horse properties on both sides of La Tuna Canyon Road in Sun Valley.  Homes in Burbank built into the steep slopes of the Verdugo Mountains and the many small tracts built into some of the canyons in the Verdugos are also vulnerable.

The fire  burned off plants that hold the soil in place, and the intense heat cooked resins and clays in the soil to make a hard, waterproof layer. A hard rain can wash the top several inches of sediment downhill, creating a mudslide, said Mike Miranda, a civil engineer with the Los Angeles County Department of Public Works.

What other kinds of parcels could get too much mud and debris?

Village Christian School is on the perimeter of the burn area. Village Christian, a K-12 private school, is surrounded on three sides by steep hills that burned close to campus.

Facilities manager Mike Custer said the school had put up some small barriers and sandbags as protection from the predicted El Niño rains two years ago, but this fire calls for another level of protection.
 
"Now we have quite a bit of concern because we're going to get so much more debris, and if we get a big storm and we're not prepared for it, there'll be major issues," he said.

Miranda estimated that one hillside behind the school's sports field could release a thousand cubic yards of mud onto the campus. A cubic yard is about the size of a washing machine.

The school has plans to shelter its 1,100 students in the gym and buildings that are more distant from the slopes during heavy rains, Custer said. 

"If we get a couple of feet of mud coming down then obviously we'll do whatever's best to protect the student body absolutely, the students first and the buildings second," Custer said.

Los Angeles Unified School District's Vinedale Elementary School is also on the perimeter of the burn area, although it is farther from the slopes.

What help are homeowners and businesses getting to reduce the risk?

Los Angeles County Department of Public Works has dispatched teams of engineers to knock on doors and speak to occupants of each of the 340 burn area-adjacent parcels. They inspected properties and provided custom plans for owners to install barriers to steer the mud between homes and out to streets and other flat areas.

The USDA's Natural Resources Conservation Service does a damage assessment of the burn area and sends its recommendations to reduce the mud and debris risk to local governments, in this case, to Los Angeles County and the cities of Los Angeles, Burbank and Glendale.

The local governments can then enter agreements with NRCS to sponsor the work, which in most cases, is on public land. The local governments would pay for the work up front and then get reimbursed for 75 percent of the cost.

Los Angeles County Board of Supervisors has already authorized spending up to $20 million to prevent and repair damage from mud flows expected in the next few months.

But private landowners like Village Christian School and homeowners on burned slopes are generally on their own to hire contractors to install barriers, sandbags, and other measures.

"This is a do it yourself job," said Eric Baumgardner, emergency services coordinator for Burbank. "Unfortunately it is private property, and the city is not able to go on private property to do any of this mitigation work."

The fire was not declared a federal emergency, so money from FEMA for loans is not available.

What's the plan for notifying residents in case of emergency?

Los Angeles city has been working to identify cell phone towers within the burn area, creating a "geo-fence" boundary within which smart phones can receive emergency messages. The LAPD has been testing the system and on Wednesday sent out a test alert, said Village Christian's Mike Custer.

The city is also requesting residents to sign up to receive notifications over its NotifyLA system. Landlines in the targeted message area are automatically included, but users of mobile phones need to opt in to receive notifications.

The Department of Public Works has distributed detailed maps of the burn area to local police and fire agencies. The maps are marked with areas that most likely will need to be evacuated if it looks like mudslides are imminent.

Baumgardner said that it's important that people heed warnings to leave their homes before mud starts to flow between properties to the street. But if they stay behind, the city asks residents to stay put until the mud is cleared away.