A storm system promising “substantial precipitation,” along with a flash flood watch and significant snowfall in the mountains, is expected to land in Riverside County Thursday.
The National Weather reported the flash flood watch for the Riverside County valleys and Inland Empire, and for the mountains below 5,500 feet, beginning Thursday afternoon and extending into Friday afternoon. Burn areas could be susceptible to mudslides and debris flow.
Mandatory evacuations were issued for select neighborhoods near the Apple Fire and El Dorado Fire burn areas.
⚠️MANDATORY EVACUATIONS ⚠️
Road closures are expected throughout the day. Please leave as soon as possible. https://t.co/YnSxghie2P
— San Bernardino County Fire (@SBCOUNTYFIRE) January 28, 2021
Showers will develop Thursday afternoon and evening, becoming more widespread late Thursday into Friday. The heaviest rain is expected to begin before midnight, lasting through Friday morning in the Inland Empire.
There is also a slight chance of thunderstorms Thursday night and Friday. Rain totals of 1.25 to 1.50 inches, and locally up to 1.70 inches, are expected in the valleys and Inland Empire, with totals 2-3 inches on the coastal slopes of the mountains below 5,500 feet.
The NWS warns residents to know escape routes and be ready to act immediately and heed all evacuation orders.
In the valleys and Inland Empire, high temperatures are expected to reach 60 to 65 Thursday but fall to 38 to 44 Thursday night.
Friday, thunderstorms are possible along with locally heavy rainfall with highs 50 to 55.
In the mountains, it will be partly cloudy Thursday morning with highs 48 to 57. It will turn mostly cloudy Thursday night into Friday, with showers increasing, possible locally heavy rainfall and patches of fog.
Snow accumulation could be 5 to 7 inches starting at 5,500 feet Friday, dropping to 4,500 feet Friday night.
The weather pattern marks the third storm system to hit the area in recent days.
Monday, the second of those three winter storms pounded the county and created hazardous conditions.
Just north of San Jacinto, icy road conditions were blamed for a six- vehicle crash Monday that left at least one person injured.
The chain collision happened about 8 a.m. on Highway 79, near Gilman Springs Road, according to the California Highway Patrol.
The vehicles collided on the northbound side of the four-lane corridor. A van went down a steep embankment, injuring the driver, who tumbled out of the vehicle, according to reports from the scene.
Light rain and drizzle passed through the area in the predawn hours, and the precipitation apparently froze on the blacktop.