When it rains in the mountains, there's a lot more stuff besides water that finds its way into Southern California's rivers and washes. There's also mud, rocks, roots, trees, limbs, leaves and rocks. And maybe a few unmentionables.
In fact, an estimated 500,000 cubic yards of debris has found its way into the foothill communities during the past week. That's where the area's debris basins come into play. Maybe you've heard about them. Without the basins, officials say there would already be big trouble in La Canada Flintridge and surrounding communities.
On Monday, dump truck after dump truck hauled away some of that stuff from those basins. The hope is that they can get rid of it now, to get ready for the next batch.
Gail Farber, Los Angeles County Director of Public Works, is personally overseeing the cleanup at the debris basins that protect homes near the Station Fire burn area. She's especially concerned about basins that nearly filled up during last week's rain, like the Mulally Basin, which is more than half full.
"We're prioritizing our debris basins," said Farber. "So some of the more critical ones -- our smaller ones -- are being cleaned out first."
Farber says the larger basins are doing exactly what they're supposed to do. She calls it "dewatering," which means the rainwater slowly filters away, leaving a massive pile of muddy mess. That way, the water drains in a controlled way, and the messy leftovers can be hauled away in trucks, often to places that need the material for fill.
It was all going remarkably well by Monday afternoon. But that could change if this week's rains are heavier than expected.
"We're hopeful this week's storm won't have the capacity of last week's storms," said Bob Spencer, a Public Works supervisor.
The water runoff that was a torrent just a few days ago is now trickling like a creek in dangerous places like Blanchard Canyon. That's great news. Officials say they are pleased for the most part with how well the debris basins are holding up.
But there's still a lot of debris up in the mountains that could be flushed out of the hills. So the Public Works Department suggests that people in the burn areas keep their sandbags handy.
Gail Farber likes to say that the debris basin is the first line of defense, but communication is a close second.
"We're not through it yet," said Farber. "Everyone needs to stay on alert and stay informed if potential storms move into the area and have significant intensities."