Vegetation fire near Monticello Dam in Napa County temporarily blocks Highway 128

Crews were containing a vegetation fire near the Monticello Dam in Napa County, according to Cal Fire.

Fire officials said that around 3 a.m. Thursday, crews responded to the wildfire reported at Lake Berryessa near the dam.

Cal Fire said the blaze was on steep, rugged terrain on the lake side of state Highway 128, burning an acre of brush and grass before crews stopped its forward progress.

Both lanes of the highway in the area were closed in both directions before officials announced their reopening past 5:30 a.m. The fire was 50% contained as of 6:20 a.m.

The cause of the fire was under investigation, according to Cal Fire.