The deadly Christmas Day mudslide that buried a church camp in the San Bernardino Forest may be only the beginning of what scientists and flood experts fear will be five years of dangerous debris flows in Southern California -- the prolonged aftermath of this year's massive wildfires.
Even before the October-November fires were fully extinguished, geologists and flood control engineers cautioned that the chances of catastrophic landslides in the charred areas had increased exponentially.
The peril is particularly grave in the canyons and foothills of San Bernardino County, where development has crept closer to the mountains in recent years. But experts said other fire-damaged areas, such as those in Ventura and San Diego counties, are also vulnerable.
"This event -- this demonstrates the degree of human hazard that we are talking about with these landslides," said Douglas Hamilton, an expert with the environmental consulting firm Exponent who has studied the landslide risks in San Bernardino County and has warned of perils since the fires.
"Prior to this situation, I think some people were discounting the dangers of these slides," he said. "This was a situation where obviously some people were camping where they should not have been, but it does give everyone an indication of what can happen, even in residential areas, during a heavy storm. It really hasn't rained much yet, and we are already seeing some serious problems."
Federal landslide experts recently issued a detailed warning on the areas vulnerable to disaster in San Bernardino County -- a warning that specifically mentioned the Waterman Canyon site of the campground -- and local officials launched a campaign to inform residents.
But the threatened regions include mountain communities that are home to thousands of people and the locations of numerous critical roadways. Not everyone has heeded the warnings to stay out of the canyons during strong rains, and because of the extent of the fire damage, authorities said, they would have to close off a large portion of the mountains to keep everyone out of harm's way in such conditions.
More than 3 inches of rain fell in the areas where mudslides occurred Thursday -- a substantial downpour, but nothing compared with the concentrated storms that spawn what experts consider 25- and 100-year floods. Nonetheless, it was clearly enough to cause widespread destruction.
