A state of emergency has been declared after days of unrelenting rainfall from a severe winter storm flooded more than 2,000 homes and businesses across two towns in California’s Sonoma County.
The towns of Monte Rio and Guerneville, about 70 miles north of San Francisco, were surrounded by floodwaters after the nearby Russian River overflowed.
Around 3,600 people have been evacuated, but roads have become impassable and the area is currently only accessible by boat, according to reports.
Governor of California Gavin Newsom issued an emergency proclamation to help communities respond to and recover from the event, which has also caused mudslides, erosion, power outages, and damage to critical infrastructure.
The affected areas have been caught in what meteorologists call an ‘atmospheric river,’ which is a long, narrow stretch of water vapour that can cause heavy rainfall and flooding when combined with strong winds.
The U.S National Weather Service reported that Sonoma County’s Russian River swelled to 46 feet on Wednesday night, more than 14 feet above flood stage and the highest level it has been in around 25 years.
Elsewhere in northern California, the winter storm has resulted in heavy snowfall, with some areas receiving up to 40 inches over a 24-hour period.
Authorities noted that parts of Northern California are particularly vulnerable to flooding following last year’s devastating wildfires, which left vast swathes of ground charred and unable to absorb rainfall, producing dangerous run-off conditions.
Sonoma County was hit by the Tubbs and Nuns wildfires in October 2017, which burnt through 36,807 acres and 54,382 acres, respectively, and destroyed around 7,000 structures between them.
While there is not yet any estimate of the extent of re/insured losses, the widespread nature of the damage is sure to trigger some losses, and the industry will be watching developments closely as more information emerges.