1. Home
  2. Caltrans Near Me
  3. District 4
  4. District 4 Current Projects
  5. Landslide on State Route 116 West of Monte Rio in Sonoma County

Landslide on State Route 116 West of Monte Rio in Sonoma County

Caltrans Has Implemented One-way Traffic Control

Update January 9, 2026
Caltrans hired an emergency contractor who arrived at the site yesterday to stabilize the highway.  Using a crane with a large auger, the contractor drilled through the pavement and earth below the eastbound lane, lowered steel beams into the holes, and backfilled them with gravel.  
Although the steel beams aren’t interlocked to create a solid wall, they are aligned close enough together to stabilize the road until a permanent retaining wall is designed and built. 

 

 Auger  Measuring the Hole  River View
 Slide side view  Installing PileInstalling Pile II  Grouting into Place

 

 

January 7, 2026 - Weeks of heavy rain and a swiftly flowing Russian River have caused the earth to give way along the eastbound shoulder of Route 116 between Duncan Road and Monte Cristo Avenue just west of Monte Rio in Sonoma County.

The slide happened at about 4:00 PM on Monday, January 5, taking out guardrail and trees, undermining a 40-foot section of the eastbound shoulder.  By the next day, the slide had grown to 100 feet in length. 

Caltrans maintenance crews have put the road under one-way traffic control as project managers work to secure funding and engineers consider design options to repair the subsiding road.

It is likely that repairs would involve two stages, one to temporarily bolster the road and another to make long-lasting repairs. In the meantime, the damaged road will likely remain under one-way traffic control.

One lane remains open to traffic on State Route 116 near Monte Rio in Sonoma County while a Caltrans employee inspects a landslide along the eastbound shoulder of the roadway.Damage affects the shoulder and guardrail on State Route 116 in Sonoma County where the hillside has slid towards the Russian River.