More than 200 homes in La Cañada Flintridge and La Crescenta were at risk of being evacuated early Wednesday morning, when a powerful storm surge was expected to bring heavy downpours, flooding and hail to already rain-soaked hillsides.
Los Angeles County officials on Tuesday issued evacuation orders for up to 147 homes in La Cañada and 85 residences in La Crescenta, but the exact number, they said, wouldn't be known until the full force of the storm reached the region.
"We have an entire watershed — 250 acres…ready to move," Mark Pestrella, deputy director of the county flood control district, said at a news conference Tuesday night.
Glendale neighborhoods, where debris basins were at just 5% of capacity Tuesday evening, did not receive evacuation orders.
County officials warned residents to obey evacuation orders because they wouldn't come lightly. After the mudflows early this year, officials were able to draft more targeted maps of properties that were at higher risk of damage, they said.
"If we are knocking on your door, you should really heed our evacuation orders," sheriff's Cmdr. Anthony Le Berge said.
Those who refused to go would be asked to sign a liability waiver, officials said.
As of Tuesday night, foothill debris basins that had been excavated and expanded over the summer appeared to be accommodating the deluge, with most of the damage confined to street flooding, falling tree branches and loosened embankments in backyards.
County Department of Public Works spokesman Bob Spencer said the Mullally, Pickens and 26 other debris basins in the foothills appeared no more than 15% full just before 6 p.m.
"Debris basins can often appear full, but only be filled with water [and not sediment]," Spencer said. "If you don't know how the basins operate they can look full, but the water is working its way through and going down the flood control channel."
The foothills and mountains could see 4 to 8 additional inches of rain on Wednesday, according to the National Weather Service, although the storm was expected to pass through the area more quickly.
Near the top of Ocean View Boulevard in La Cañada, resident Nick Selemi said he would not be leaving his home and continued making dinner Tuesday evening despite evacuation calls.
When the Mullally basin overflowed in February, he said, other residents who had stayed behind then took shelter in his home, which was largely spared from mudflow damage.
"Last time it was OK," Selemi said, expressing more concern for his Manistee Drive neighbors, where at least two homes appeared vacant and still under reconstruction from debris-flow damage early this year. "A lot of them just finished rebuilding their homes."
The Red Cross established an evacuation center at Holy Redeemer Church at 2411 Montrose Ave. in Montrose.