Three grass fires ignited Tuesday near U.S. Highway 101, in the hills above Sausalito, according to the Marin County Fire Department.
Mill Valley police issued an advisory at 12:20 p.m. urging people to avoid the area of Cloud View Road and Wolfback Ridge Road because of the fires, which sparked north of Rodeo Avenue.
Firefighters have halted the forward march of the fires, officials said around 1:15 p.m., but they were still keeping an eye out for spot fires. The flames consumed about 4 acres.
Crews were expected to remain at the scene overnight as a precaution because of dry conditions.
The blazes prompted the closure of all southbound lanes of Highway 101 initially. The far left lane north of Spencer Avenue reopened by about 2:40 p.m., and the No. 2 lane reopened about 3:45 p.m., according to the CHP.
The right two lanes remained closed, and there was no estimated time for reopening those lanes.
By about 6 p.m., the fires were 90 percent contained, officials said.