Five days before the storm, forecasters began notifying emergency managers, the media and the public about the approaching system, which was predicted to pound the Thomas fire burn area.
After the Thomas fire, the U.S. Geological Survey studied the burn area to determine its vulnerability for flash floods, mudslides and debris flows. The agency found that a rainfall rate of half an inch per hour would trigger debris flows, officials said.
On Tuesday morning, the storm far exceeded that threshold when it dumped 0.54 of an inch of rain on Montecito within five minutes, said Robert Munroe, a meteorologist with the National Weather Service in Oxnard.
Munroe said such an extreme rainfall rate is usually seen once every 200 years.
The day before the storm hit Montecito, about 60 Santa Barbara County sheriff's deputies and search and rescue workers spent hours roving the community's foothill neighborhoods, trying to persuade people living in the shadow of scorched mountains to leave.
County officials also issued mandatory evacuation orders for about 7,000 people living north of Highway 192 in areas closer to where the Thomas fire had burned. Voluntary orders were issued for 23,000 others as the storm approached. Residents in those areas were not visited by sheriff's deputies, officials said.
Tom Fayram, a deputy public works director, said that whether the county issues mandatory or voluntary evacuation orders, they should be taken seriously.
"Voluntary evacuation doesn't mean you don't have a problem," he said. "If we felt they did not have a problem, we would not have issued a warning at all."
Some of the hardest-hit areas were in the voluntary evacuation zone south of Highway 192, and it's clear many residents there stayed in their homes.
The upscale town -- home to such celebrities as Oprah Winfrey -- is situated between the Pacific Ocean and Los Padres National Forest. The Montecito Fire Protection District's wildfire protection plan, released in February 2016, notes that the town's semirural character -- its narrow and steep roads, addresses not clearly visible from the street, and unlit roads and intersections -- pose problems for emergency responders and evacuating residents.