A ten-ton boulder that diverted drainage off a mountain side sent mudslides through an L.A. neighborhood evacuating 500 homes and entering 43. "An unexpectedly powerful rainstorm unleashed a torrent of mud that inundated more than 40 houses Saturday, leaving La Cañada Flintridge's northernmost neighborhood awash in boulders, dented cars and broken homes. The force of the mudflow appeared to catch residents and officials off guard, as the forecast initially called for a light to moderate rainstorm. No evacuations had been ordered Thursday or Friday, when the rain began to fall. But before dawn on Saturday, an intense band of rain cells formed over the mountains burned in the massive Station fire. What was supposed to be a fast-moving storm instead stalled, dumping rain at an alarming rate. The power of the debris flowing off the mountain pushed a 10-ton boulder into a critical catch basin in La Cañada Flintridge. The boulder clogged the drain like a giant stopper and the ashen muck had nowhere to go but through the Paradise Valley neighborhood on the northern end of Ocean View Boulevard. Mud flowed two miles downhill, all the way to Foothill Boulevard. 'It looked like the Niagara Falls was coming down the street,' said Amanda Manukian, who lives in the 5400 block of Ocean View Boulevard. She said she saw firefighters scramble out of her neighbor's home when a burst of rainfall poured down, threatening the crew."