The two cities, which sit below the Colby Fire burn area, issued a mandatory evacuation order at noon Thursday ahead of the stronger storm system that moved into the Southland late Thursday night and intensified through Friday morning.
Mud, rocks and sticks started streaming down Hicrest Road at about 7:30 a.m., pooling at the intersection of Sierra Madre Avenue. Hicrest Road dead ends below some of the hillsides scorched by last month's Colby Fire.
A dozer worked to channel the mud flow to a vacant field, as crews cut open a chain link fence to clear more space for the run-off.
Glendora resident Larry Davis went outside to take his grandson to school, only to discover the road outside his home was blocked by debris.
"It's probably worse than what I anticipated would happen," Davis said. "I didn't know all this debris was going to be coming down."
Mario Vasquez has lived in the area for 14 years. His home is in the area under a mandatory evacuation order, but he chose not to leave just yet. He set up sandbags to divert the mudflow away from his home, and so far, it's working.
"I was happy that there's no mud coming in the house. I mean, right at the top is where our most vulnerable spot was," Vasquez said. "This all (pointing to the muddy street) will wash away."
The first round of heavier rain brought down mud and debris faster than many Azusa residents on Ridge View Drive had hoped. It quickly filled the debris basin above their homes.
"We had about 3 feet of mud that came up against the plywood at the top of the patio. That's just a little bit of the beginning. It's just the beginning," said resident Lorenzo Tatone.