Helicopters and airplanes dumped water on wildfires and the smoldering wreckage of hilltop neighborhoods around Valparaiso for a third straight day Monday as sailors in riot gear stood ready to evacuate 700 more families whose homes could be lost if the winds shifted.

Already 11,000 people were homeless as wildfires sent burning embers flying from hilltop to hilltop. A 15th body was found, and the toll of destroyed homes rose to more than 2,500. As smoke rose from smoldering ruins all over the picturesque coastal city, many compared the scene to Dante's inferno.

Some people made their way home after days without sleep, only to discover ruins. The fires, so hot they created their own fierce winds, consumed a few entire neighborhoods. In other districts, some houses stood unscathed but remained in danger from glowing embers carried by the shifting winds.

"We are looking at the largest air operation ever assembled against a fire like this," Chilean President Michelle Bachelet said. She said the blazes had grown to "dimensions never before seen."

Chile's forestry agency predicted it would take three weeks to completely stamp out the fires, which began Saturday in a forested ravine and quickly spread into ramshackle housing on one of Valparaiso's 42 hills.

Hot dry winds blowing out to sea whipped embers onto other neighborhoods on six densely populated hills where people live in poorly constructed homes without municipal water or sewer connections, fire hydrants or streets wide enough for emergency vehicles.

On Monday, there was no end in sight. Helicopters were flying without pause, dumping water on hotspots.

Aid was flowing in from all over Chile to Valparaiso, where evacuees crowded into eight shelters. Hundreds of young volunteers climbed hills carrying bottles of water and shovels to help victims search the ruins of their homes.

"We're going to rebuild right here. Where else would we go?" said Carolina Ovando, 22, who lost the humble home she kept with three small children.

Schools were closed, some of them damaged by fires and others jammed with evacuees.

Navy officer Julio Leiva said Monday that the death toll rose to 15. Most of the bodies were too badly burned to identify without DNA tests, the national forensics service said. More than 500 people were treated at hospitals, mostly for smoke inhalation.

Bachelet coordinated the emergency response with her Cabinet, cancelling a trip to Argentina and Uruguay. She asked Chile's neighbors for backup in case of other fires, freeing Chilean planes and helicopters to join the fleet in Valparaiso.

Argentine Foreign Minister Hector Timerman promised to collaborate with rescue teams and water-dumping planes. From the Vatican, Pope Francis sent a message sharing his prayers.

Bachelet put the entire city under military rule, and 5,000 firefighters, police, forest rangers, soldiers, sailors and civil defense workers joined the response. Cars were banned from streets leading up eight of the Valparaiso's hills so emergency vehicles could get through.

Valparaiso is an oceanside city of 250,000 people surrounded by hills that form a natural amphitheater. The compact downtown includes Chile's congress and its second-largest port, and the city owes its status as a UNESCO World Heritage Site to the colorful homes built on slopes so steep that many people commute using stairs and cable cars.

But what's beautiful on postcards can be dangerous for those who live there: Many people have built on land not fit for housing.

"We are too vulnerable as a city. We have been the builders and architects of our own danger," Valparaiso Mayor Jorge Castro said Sunday in an interview with Chile's 24H channel.