Several grass fires broke out on the mid-Peninsula in Thursday's scorching heat, one of them resulting in the death of a homeless woman in East Palo Alto.

The woman was found dead by officers responding to a grass fire that started in a small homeless encampment near East Palo Alto's levees at the end of Demeter Street. Police questioned a man who had been with her and was rescued unscathed from the fire.

The man and woman were inside a makeshift shelter that had been dug into the side of the hill and stabilized with the roll bar of a jeep or truck.

The fire started about 4:40 p.m. and burned through two grassy acres before it was fully contained by 5:50 p.m.

"Our investigators are looking into the cause," Menlo Park Fire Protection District Chief Harold Schapelhouman said. "Based on the volume of fire that was coming out of that area, the shelter is a major point of interest."

East Palo Alto police arrived first on the scene and managed to pull the man out of the shelter before he was burned, Lt. Tom Alipio said. The officers attempted to re-enter the small cave, but the fire had grown to dangerous levels, Alipio said. The woman was found burned almost to her bones, he added.

"They tried to get her, but the flames were too high and the heat was intense," Alipio said. "Those officers' actions were very heroic."

Shapelhouman said none of the nearby structures, including the Romic Environmental Technologies waste handling site