The death toll from a mudslide in California rose to at least 17 people on Wednesday as rescue crews continued to search for another 17 missing people.  

Hundreds of firefighters and others sifted through mud and debris in Montecito, a town 145 kilometers (90 miles) northwest of Los Angeles, after powerful rainstorms triggered a mudslide on Tuesday.

With many roads blocked, rescue crews used helicopters to pluck people from their rooftops.

The Thomas fire scorched much of the region last month in what was the largest wildfire ever recorded in California.

With heavy rain forecast, authorities had ordered evacuations beneath the burned areas of Santa Barbara, Ventura and Los Angeles counties, but only 10 to 15 percent of residents heeded the orders, according to the Santa Barbara police department.

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The worst rainfall came at 3.30 p.m. local time (2330 UTC) on Tuesday, when Montecito received more than a half inch (1.3 centimeters) of rain in a five-minute period. With the wildfires leaving behind a waxy layer of debris that made it difficult for water to infiltrate the ground, the downpour caused flash floods in the fire-scarred Santa Ynez Mountains.

The flash floods caused mud and boulders to roll down hills, turning roads in to mud rivers and ripping homes off their foundations. Authorities said more than 100 homes had been completely destroyed and another 300 damaged. 

American talk show host Ellen DeGeneres, who has a residence in Montecito, tweeted a picture of US Highway 101, which was turned into a giant mud river. Oprah Winfrey and Rob Lowe also have residences in the area.

With roads blocked, rescue crews used helicopters to pluck people from their rooftops.

cw,dv/se (AFP, AP, dpa, Reuters)