As one huge fire after another ran wild in the California hills during last year's record-setting wildfire season experts warned that destructive debris flows would soon follow. They were right about that—but as each new rain event raises risks of another boulder-loaded mudslide, it's becoming obvious that predicting just where and when the killer landslides might happen is not so easy.

Storm forecasts prompted fresh evacuations in mid-March in Santa Barbara County, where the huge Thomas fire led to killer debris flows back in January. This time around, the storm effects were minimal. But as the storm approached, local papers advised residents that their personal risk would be very hard to estimate.

"As a powerful storm nears the South Coast, the pre-evacuation advisory for 'anyone who lives near a burn area in Santa Barbara County' conveys a painful reality," reported the Santa Barbara Independent (see: "Next Debris Flow Could Take Different, Unknown Path," by Melinda Burns: "No one knows when or where the next torrent of mud and boulders will come surging down the scorched mountainside into town."

"But it’s a good bet that it could happen, given enough rain," the paper explained: "According to a recent report by a team of state hydrologists and geologists, 50 out of 138 streams and tributaries in the mountains above Montecito and Carpinteria have a 60 percent or greater likelihood of producing debris flows in the aftermath of the Thomas Fire, based on a rainfall rate of about 1 inch per hour."

The March storms moved on without causing major damage, reported Los Angeles TV station KNBC (see: "Southern California Recovers After Mud, Debris Flow Following Spring Storm," by Kevin LaBeach and Karla Rendon): "The storm swelled rivers, flooded streets and triggered water rescues statewide over three days but spared communities a repeat of the deadly debris flows that occurred during a January deluge. Several roads were affected by the storm's debris, including Highway 1, where all lanes across Mondos Beach are blanketed with mud, according to California Highway Patrol."

But uncertainty about the long-term future risk is holding up the rebuilding plans of hundreds of residents who live downhill—and downstream—of the Thomas Fire burn area, reported the Coastal View News from Carpinteria, California (see: "Remapping Montecito and Carpinteria, post-apocalypse," by Melinda Burns).

"Last week, the owners of a one-story home on Santa Elena Lane sought preliminary approval from the Montecito Board of Architectural Review for an 800-square-foot addition and a new wall in the front yard to deflect floodwaters from Montecito Creek," the paper reported. "The Jan. 9 debris flow carried mud right up to the house but not inside it. The property was green-tagged; county inspectors did not find any structural damage. But on Thursday, planners put the proposed addition on hold until FEMA, the Federal Emergency Management Agency, draws up a 'recovery map' for Montecito."

The county policy applies to 350 homes in the affected area, the paper reported: "They have been advised by the county not to spend money on their rebuilding plans until FEMA finishes its work." FEMA's re-mapping efforts are likely to identify new hazard areas outside the existing hazard maps, the paper reported. Meanwhile, hundreds of property lines that were buried by the flows need to be re-surveyed—a process that will have to wait until the county has placed 70 new benchmarks for a new "control network" for surveyors to reference.

And the next map FEMA produces won't be final: "It will take FEMA four or five years to draw up the more comprehensive Flood Insurance Rate Maps that the county uses for long-term floodplain management," the paper reported. Bottom line for now, according to FEMA engineer Eric Simmons, who heads up the remapping effort? "Those who survived this disaster are at high risk for another event," he said. "That’s why we’re working together and encouraging new development to be safe."