Fire officials kept a close eye on weather patterns Thursday as they prepared to torch a house so laden with explosives that authorities have no other choice but to burn it to the ground.

Wind currents and other weather patterns are hugely important in the highly controlled burn operation because authorities do not want a smoke plume to spread throughout the heavily populated suburban area. The burn was originally set to occur at 9:30 a.m. local time but was delayed for an hour or more to make sure the weather is right.

Arson officers opened windows and doors while holes were drilled in the roof to ensure adequate ventilation for the fire. Authorities were given protective breathing masks in case they must enter the house if the blaze got out of control.

Before torching the home, officials were awaiting wind conditions that would allow the smoke to go straight up in the air.

"It will burn very hotly, very quickly," said Jan Caldwell, a spokeswoman for the San Diego County Sheriff's Department. "We want everybody to do this job safely and go home to their family."

Tim Latulippe, whose backyard borders Jakubec's property, said he was sure the burn would go off without a hitch. He hoped to watch it live on the Internet with his automotive students at Escondido High School. His wife planned to watch from the family camper, parked at a friend's house across town.

"They're going to burn a house down, it's going to be cool, and we get to go back to our normal lives," Latulippe said as the family prepared to evacuate.

The house was rented by an out-of-work software consultant who allegedly assembled an astonishing quantity of bomb-making materials that included chemicals used by Middle Eastern suicide bombers. Investigators are still trying to understand his motivation for allegedly possessing the material.

Bomb-squad experts determined the residence was too dangerous to go inside, so they drew up plans to burn it down. The home is so cluttered with unstable chemicals that even bomb-disposing robots can't be used to enter it.

The fire is expected to reach about 1,800 degrees Fahrenheit — hot enough to neutralize the unstable explosives inside.

Sheriff's deputies knocked on doors Wednesday night to urge scores of residents to leave before the fire. People farther away were told to close their windows and stay inside during the burn.

Crews have built a 16-foot firewall and covered it with fire resistant gel to protect the closest homes. Officials also planned to close down a section of Interstate 15 during the fire that will be monitored by more than a dozen air pollution sensors.

San Diego County Sheriff Bill Gore said the burn was expected to last one to four hours.

"It has to be dealt with at some time," Gore said outside San Diego's federal courthouse Wednesday after a judge denied a defense attorney's request to delay the burn. "Our belief is the sooner, the better."

George Jakubec, a 54-year-old unemployed software consultant who rented the Escondido home, has pleaded not guilty to charges of making destructive devices and robbing three banks.

Nearly every room is packed with piles of explosive material and items related to making homemade bombs, prosecutors said. In the backyard, bomb technicians found six mason jars with highly unstable Hexamethylene triperoxide diamine, or HMDT, which can explode if someone steps on it.

A coffee table was found cluttered with documents and strewn with detonators, prosecutors said. A bowl of white powdery HMDT also was found.

"The coffee table is what the bomb squad calls ground zero," Assistant U.S. Attorney Rees Morgan told the judge. "This really was an assembly line for detonators being created in his house. ... It is a no-go zone."

Bomb squad officers who inspected the property believe Jakubec has manufactured so many devices for so long that "even he has forgotten the location and type of explosives stashed throughout the property," prosecutors said in a court filing.

Officers said they found the same types of chemicals used by suicide bombers and insurgents in Iraq and Afghanistan. The materials included Pentaerythritol tetranitrate, or PETN, which was used in the 2001 airliner shoe-bombing attempt as well as airplane cargo bombs discovered last month by authorities.

The chemicals were found after a gardener accidentally set off an explosion at the home by stepping on what authorities believe was a byproduct of HMTD.

Defense attorneys wanted to delay the burn to allow more time to collect evidence, including notes scribbled on graph paper and a hardcover book about mining.

But U.S. District Judge Larry Burns accepted testimony of FBI bomb expert James Verdi, who said it would be irresponsible to allow anyone to enter.

Verdi, a veteran of wars in Iraq and Afghanistan who was inside the home several times, testified that the HMTD found was "an amount we had never seen, either domestically or internationally."

"My first entry into the backyard, it was like we were entering into a minefield," he said.