A final round of precipitation, possibly the heaviest of the week, fell over the Inland Empire Thursday, prompting authorities to issue mandatory evacuation orders for several western Riverside County communities in the Holy Fire burn area, as well as raising the risk of flash flooding, mudslides and debris flows throughout the region.
The National Weather Service issued a flash flood watch for the Riverside County mountains and valleys through Thursday afternoon.
“The greatest threat for flash flooding (in Riverside County) would be between 8 a.m. and 5 p.m. Thursday,” the NWS statement said. “With the heaviest rain still to come on top of recent rainfall already soaking the ground, urban flooding is likely and flash flooding is certainly possible anywhere within the watch area.”
Evacuation orders are in effect for neighborhoods throughout the Temescal Valley and just north and west of Lake Elsinore, including Amorose, Alberhill, Glen Ivy, Glen Eden, Grace, Horsethief Canyon, the Laguna “A” zone, Maitri, McVicker, Rice and Withrow.
The agency issued voluntary evacuation warnings to residents in the Alvarado and Laguna “B” zones Wednesday afternoon, based on the prospect of major runoff, mud and debris flows.
As of 10 a.m., the storm systems over the past four days had dropped 1.64 inches of rain at the Riverside Municipal Airport, 1.61 inches in Temecula, 3.38 inches in Lake Elsinore, 6.9 inches near upper Horsethief Canyon, 2.91 inches in Idyllwild, 1.7 inches in Beaumont and .95 of an inch at the Palm Springs International Airport, according to the NWS.
Up to three-quarters of an inch of rain is forecast Thursday for the Riverside metropolitan area with around six-tenths of an inch predicted in Lake Elsinore, forecasters said. The San Gorgonio Pass near Banning could see up to eight-tenths of an inch of rain and the Coachella Valley was expected to get around one-tenth of an inch.
Snow levels are expected to remain above 8,500 feet.
A care and reception center was set up at Temescal Canyon High School at 28755 El Toro Rd. in Lake Elsinore to take in residents. Small animals were being accepted at the San Jacinto Animal Campus, 581 S. Grand Ave, while residents with large animals were urged to contact Riverside County Animal Services at (951) 358-7387.
The Lake Elsinore Unified School District announced Thursday that Rice Canyon Elementary School and Withrow Elementary School would be closed because of the increased risk of debris flows in nearby residential areas.
More information is available at www.rivcoready.org.
Each impacted community lies along the eastern boundary of the Cleveland National Forest, where the 23,000-acre Holy Fire in August denuded steep terrain below Santiago Peak, permitting water to flow unchecked onto lower slopes where subdivisions are situated.
Rains on Dec. 6 resulted in significant flooding and mud flows into several neighborhoods, prompting street closures and evacuations. However, there was no major damage to homes.
The NWS also issued a wind advisory for the county mountains and the San Gorgonio Pass near Banning that is set to last through 7 a.m. Friday.
The final storm system is expected to leave the region by Thursday night, and dry weather with warmer temperatures will prevail from Friday afternoon through next week, forecasters said.