Pasadena's foothill neighborhoods could see up to 2 inches of rain Wednesday, Oct. 21, and Thursday, Oct. 22, as the season's first significant storm moves through Southern California.

The National Weather Service said a low-pressure system tracking south along the California coast will bring cooler temperatures and widespread rain to Los Angeles County, the Pasadena Star-News reported. Forecasters expect three-quarters of an inch to 1 inch across the county, with totals reaching 2 inches in foothill areas and along coastal mountain slopes. There is a 25% chance rainfall could exceed those projections.

The risk is highest in fire-scarred neighborhoods.

About eight to 10 homes in Upper Hastings Ranch are on the city's watch list for possible mud and debris flows, Emergency Services Manager Nallely Procopio told the Municipal Services Committee on Tuesday, Oct. 20, Pasadena Now reported. Officials have identified properties where a debris flow could threaten safety or block access, and city personnel plan to notify those households when forecasts warrant it.

"A lot of it right now is potential," Procopio said. She added that significant storms generally come into focus seven to 10 days ahead, giving the city time to prepare and contact residents.

The risk is heightened in foothill areas affected by the Eaton Fire, Procopio said.

Public Works Director Greg De Vink said Upper Hastings Ranch is the only area where the city has seen recurring, significant mudflows. Mud has come through residents' backyards and driveways and into the road, making barriers impractical for some homes. De Vink recommended sandbags, which the city provides free.

Sandbags and storm prep

Self-serve sand and bags are available at Pasadena Fire Station 37 (3430 E. Foothill Blvd.) and Fire Station 38 (1150 Linda Vista Ave.) during significant rain events, while supplies last, according to a city press release. Sandbags are limited to 10 per person. No contractors are permitted.

De Vink said crews will also inspect catch basins, clear storm drains in areas prone to backups and keep barriers in place along New York Drive, where landslide concerns have persisted since the fire. Pasadena Water and Power is increasing inspections of electrical equipment and burned hillsides near water facilities. The utility is also preparing crews for possible outages.

Rain could begin as early as Tuesday night, with lighter precipitation expected Wednesday before showers become more widespread overnight into Thursday, according to the weather service. The storm is expected to bring about 12 hours of rain, with a slight chance of thunderstorms. Rainfall rates are not expected to be hazardous unless thunderstorms develop.

Rain should taper off by Thursday evening. Skies are expected to clear Friday, Oct. 23, with highs rising 3 to 6 degrees across the county.

How to prepare

Los Angeles County declared a local emergency on Sept. 23 in anticipation of El Niño pushing heavy rains into the region this winter, the Pasadena Star-News reported. L.A. County Supervisor Hilda Solis cited the risk of flooding, landslides and debris flows across the county. Areas where recent wildfires stripped natural ground cover are of most concern, according to the Star-News.

Pasadena officials urged residents to learn their evacuation zones and prepare supplies for at least 72 hours. The city can now issue emergency alerts directly through wireless evacuation warnings that reach phones in an affected area without registration, Procopio said. Residents can also sign up for the Pasadena Local Emergency Alert System (PLEAS) at CityOfPasadena.net/Fire/PLEAS for text and voice alerts.

Pasadena Water and Power General Manager David Reyes said residents can call 311 during a prolonged storm to reach the appropriate city department. For power emergencies, call Pasadena Water and Power at (626) 744-4673.