Dense Fog — San Bernardino County Mountains, California

2019-01-16 · San Bernardino County Mountains, California

Event narrative

Local media reported a 19 car pileup on southbound I-15 in the Cajon Pass due to dense fog in the morning hours of January 16th. 35 patients were treated for minor to moderate injuries.

Wider weather episode

A high impact mini atmospheric river impacted Southern California January 14th and 15th which brought heavy rain and snow to the region. Seal Beach reported 2 inches of rain in 2 hours, which caused extensive flash flooding. Water was up to doorways outside of homes, and the Pacific Coast Highway was closed for over a day in Huntington Beach due to flooding. Rainfall rates remained below flash flood thresholds at the Holy and Cranston burn scars during this mini-AR event. Dense fog was reported in the Cajon Pass on the morning of January 16th, which resulted in a 19-car pileup and 35 patients with minor to moderate injuries.

A larger atmospheric river moved into Southern California on January 17th, bringing heavy rain and snow to the region. Extensive flash flooding occurred due to the heavy rain. Swift water rescues occurred on the Santa Ana River in Riverside due to flooding. Rainfall rates exceeded flash flooding thresholds for the Holy fire burn scar on the 17th.

Overall, 6 to 12 inches of rain fell in the Santa Ana and San Bernardino County Mountains between January 14-17. Snowfall amounts in the mountains ranged from 4 to 12 inches above 6500 ft. Major surf and coastal flooding occurred during this event as well, which resulted in extensive damage of the Ocean Beach Pier in San Diego County.

Source: NOAA Storm Events Database, event_id 805124. Narrative written by the NWS forecast office that issued the report.