Commuters were faced with train delays and cancellations Thursday in Acton, where the storms caused heavy flooding.
"The flash floods, which washed out roads and caused mudslides, also washed out tracks between Metrolink's Via Princessa and Vincent Grade/Acton stations," Metrolink spokesman Scott Johnson said.
Antelope Valley Line trains 200 and 202 between Lancaster and Los Union Station have been canceled, Johnson said. The first train to operate will be Antelope Valley Line train 204, departing Lancaster at 5:19 a.m., he said.
Metrolink also will operate Antelope Valley Line train 285, which makes limited stops between Palmdale and Union Station.
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"Friday's schedule is subject to change and is dependent on the railroad tracks being repaired overnight between the Via Princessa and Vincent Grade/Acton stations," Johnson said. "Due to the track repairs, trains that do operate will likely proceed at reduced speeds, which will lead to delays."
Hot tropical weather earlier Thursday spawned thunderstorms that sent flood waters rushing through the Acton area, halting Metrolink service and prompting the evacuation of about 200 train passengers.
National Weather Service forecasters had issued a flash flood watch for the San Gabriel Mountains and the Antelope Valley as "copious amounts of monsoonal moisture'' streamed across Southern California throughout the day Thursday. The flooding in Acton was caused by an intense 30-minute midafternoon downpour that also inundated parts of the Antelope Valley (14) Freeway and Sierra Highway.
A hoist rescue of a main from the roof of a pickup truck that became stuck in rushing water occurred about 5:20 p.m. Thursday in the area of Syracuse Avenue and Crown Valley Road, where flood waters swamped several properties. Overall, the Los Angeles County Sheriff's Department reported that county firefighters performed three air rescues of stranded motorists.
No injuries were reported.
Flooded and possibly undermined tracks near Aliso Canyon Road also brought the Metrolink train to a halt in the area, and officials later announced service was halted between Via Princessa and Lancaster on the Antelope Valley Line.
About 200 people were evacuated from the stopped train, according to a Los Angeles County Fire Department dispatcher. Metrolink was working to secure alternate transportation for stranded passengers, according to the sheriff's department.
The county's Department of Public Works was also working to clear roadways after receiving multiple calls about mud and rock debris. An NWS statement had warned that flash flooding and debris flows would be a threat especially in areas previously denuded in wildfires.
Temperatures around 100 degrees were reported Thursday in some valley and desert locations, but today's highs are expected to be a bit lower as things cool off for the weekend. The NWS said there might be an isolated thunderstorm today over the eastern San Gabriel Mountains, but estimated the chance of any further thunderstorms to be less than 15 percent.