Highway 101 is closed between Mendocino and Humboldt counties, after a second landslide cut the road through at least Friday, according to Caltrans.
The Santa Rosa Press Democrat first reported on Wednesday that for the second time in two months, the two-lane section of highway in northern Mendocino County, about 10 miles from the Humboldt County line, was closed after a series of heavy thunderstorms and rapid temperature changes caused steep water-saturated hillsides to collapse.
— Times-Standard (@eurekaTS) April 20, 2017
The first landslide featured several big boulders, but the second slide contained over 6,000 cubic yards of soil, rocks and debris.
The first landslide on March 10 in the adjacent area of Bridges Creek shut down the main north-south connection for about a day. But Caltrans estimates that the new rock slide will shut down 15 miles of Highway 101 until at least Friday, April 21.
Traffic on the 101 in northern Mendocino is being funneled down from two lanes to a single lane in a 5.8-mile section north of the City of Leggett due to mud and rock slide removal. Another 12.3-mile section near the Dora Creek Bridge is being restricted to one-lane controlled movements. Caltrans expects emergency repairs could last until May 31.
A 0.7-mile section of Highway 101 in Humboldt County near junction 271 is being reduced from four lanes to two lanes due to storm damage repair, and Del Norte County Highway 101 traffic south of Crescent City is currently being restricted to one-way controlled movement at various locations over a 3.2-mile section. Caltrans has not estimated when crews will be able to complete repairs to these sections of Highway 101.
With the storm system having moved inland, California temperatures rose on Thursday and Friday to 69 degrees along north state sections of Highway 101, and up to 80 degrees along Sacramento Valley sections of Interstate 5, according to AccuWeather.
Sacramento Valley temperatures are forecast to begin cooling to the low 70s as thunderstorms return mid-week. But then Northern California temperatures along Highway 101 will jump to the mid-70s and the Sacramento Valley temperatures along Interstate 5 will spike to 86 degrees in a heat wave that may cause a significant early snowmelt.
Caltrans offers about twenty webcams that operate 24 hours per day for travelers to view northern California sections of Highway 101 that may be impacted by the landslides.