Part of a major route between the San Fernando Valley and West Hollywood remained closed Thursday due to the collapse of concrete foundation for a hillside house above the road.
Laurel Canyon Boulevard was closed between Gould Avenue and Kirkwood Drive as building safety inspectors assessed the risk of further collapse sending more debris down the slope, according to the Los Angeles Fire Department. No injuries were reported.
The couple renting the house on Gould Avenue said they became aware Tuesday of a crack in the concrete foundation beneath the back deck, said Brett and Adria Copeland. As a precaution, the couple left to stay at a hotel.
Emergency responders Wednesday found a slab of concrete weighing an estimated 9 tons hanging precariously at the top of the slope, prompting authorities to shut down traffic below. At 2:30 p.m., the slab with sewer pipes suddenly slid down to the edge of the roadway, fracturing into pieces, some of which landed in the southbound traffic lane.
It appeared that the concrete slab had been undermined by water that saturated the hillside, said Glenn Miyagishima, Chief of LA City Fire Battalion 5.
Authorities indicated both directions of travel on Laurel Canyon Boulevard at this point would likely remain closed at least until engineers make an assessment, and that would not occur until after forecast storms pass through the area.
Brett Copeland, a musician with the band "Fire," said he was looking forward to a quiet night home after playing a gig Monday, but with rain in the forecast, did not feel comfortably staying another night.
"Something told me 'Hey, don't take a chance,'" said Copeland, as his wife nodded in agreement.
Inspectors red-tagged the house where they were staying -- meaning no entry -- and on the adjacent homes, hung yellow precaution tags.
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The woodsy canyon, a famed counter-culture haven in the 1960s, has steep hillsides that have been succeptible to slides that can send dirt, rocks and debris onto the road. In 1978, mud, rocks and debris washed down the hillsides, damaging at least one home and collecting cars that were carried down the canyon.
Wednesday's hillside problems followed a wet start to the year in Southern California, raising the threat of landslides and flooding. December marked downtown Los Angeles' wettest month in six years.
More rain is expected late Wednesday through Thursday morning in Los Angeles County.
NBC4's Patrick Healy contributed to this report.