Highway 37 to close for a full weekend for El Niño preparations

The stretch of Highway 37 between Sonoma and Solano counties will shut down for a full weekend next week while road crews prepare for impacts from a strengthening El Niño this winter.

Closures will cover about 10 miles in both directions between Sears Point and Mare Island, according to Caltrans. Westbound lanes will be closed 7 p.m. Oct. 21 to 4 a.m. Oct. 22 before the full, 55-hour closure goes into effect from 10 p.m. Oct. 23 through 5 a.m. Oct. 26.

During the weekend closure, eastbound motorists will need to exit onto Highway 121 near Sonoma, while westbound travelers will need to go onto Highway 29 toward Napa.

Work consists of median demolition and k-rail installation to shift all traffic into Highway 37’s westbound lanes. Afterward, crews will raise portions of the eastbound lanes by 3 feet to “improve resiliency and address flooding concerns along this vital transportation corridor,” Caltrans reported.

Additional closures are scheduled for 10 p.m. Nov. 13 to 5 a.m. Nov. 15 for crews to shift traffic into the eastbound lanes.

El Niño is not a storm or series of storms, but rather an oscillation that translates into a warming of the tropical eastern Pacific Ocean that can impact weather patterns in the northern hemisphere. Meteorologists expect the developing El Niño will strengthen into a record-breaking system, bringing a potentially severe winter to California that could significantly raise sea levels and exacerbate flooding and coastal erosion.

California Gov. Gavin Newsom declared last month a statewide emergency for California to fast-track permits for flood protection projects and allow state agencies to obtain emergency supplies without the usual competitive bidding process. Last week, the Sonoma County Board of Supervisors passed its own emergency proclamation.

Highway 37, the North Bay’s key east-west route, in particular has historically been prone to flooding. It runs along San Pablo Bay in places just feet from the water line, exposing the roadway to frequent storm-related flooding.

Sea level rise is expected to make those problems worse, and experts have for years contended the entire road could be under water within several decades. Fundraising efforts have been ongoing. Most recently, the California Transportation Commission in August approved $300 million in grants to reduce congestion and flooding on Highway 37 between Novato and Vallejo while also spurring baylands restoration.

You can reach Staff Writer Colin Atagi at colin.atagi@pressdemocrat.com.