The fire department is trying to figure out what caused a house fire that killed an elderly woman on Staten Island.

Flames broke out around 4 a.m. at a home on Driggs Street in Great Kills.

Hundreds of firefighters were called to the scene, and the FDNY declared the fire under control shortly after 7 a.m.

Police say an elderly woman died in the fire. She has not been identified, but family members at the scene told NY1 that their 83-year-old grandmother lived alone in the home.

Fire officials say they faced many obstacles at the scene.

"The heavy pile of clutter and debris kind of halted search operations and line advancement at the front door. It was very difficult to climb over it. I think there were three to five feet of debris we were met with right at the entrance doorway. So it makes it, it's not just walking in the door, it makes advancing a very difficult challenge," said FDNY Deputy Chief Brian Gorman.

The fire was so hot, it singed a house next door.

One firefighter suffered minor injuries.