SAN JOSE (CBS SF) - Four residents have been evacuated after a two-alarm fire Wednesday morning heavily damaged a San Jose duplex apartment, according to a San Jose fire captain.

A call came into the San Jose Fire Department at 2:57 a.m. about a fire at Denise Way and Almaden Road. Fire crews arrived at 3:04 a.m., according to San Jose fire Capt. Rob Brown.

Firefighters arrived to a roof and attic engulfed in flames at a single-story duplex on the corner of the intersection.

A second alarm was called at 3:07 a.m., Brown said.

Strong wind gusts made it difficult for firefighters to contain the fire to where it had started. Brown said crews were on "ember patrol" to monitor distant structures in danger of catching windblown embers.

The fire has heavily damaged both duplex units. Brown said the entire roof collapsed.

Two residents from each of the two affected units were safely evacuated. No injuries were reported, Brown said.

Around 4 a.m. firefighters were in a defensive fire mode and Brown estimated crews would be at the scene of the fire through the early morning.

(Copyright 2012 by CBS San Francisco and Bay City News Service. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)