Firefighters worked throughout the day Wednesday battling flames threatening homes atop Palomar Mountain and in nearby communities at the bottom.

The 25,000 acre Poomacha fire started on the La Jolla Indian Reservation near Palomar Mountain early Tuesday morning. It spread south and southwest by strong winds into the Rincon, San Pasqual and Pauma Indian reservations.

Fire officials said Tuesday that they expected the fire to merge with the 200,000-acre Witch Creek fire, but fire officials said Wednesday that it had not.

The fire prompted thousands of residents to evacuate their homes on from Palomar Mountain west to Pauma Valley. It burned about 60 structures at the Rincon reservation, including homes, mobile homes and other facilities, and 31 structures at the La Jolla reservation, tribal officials said.

As night fell, officials with the Pauma Band of Mission Indians said they were watching the fire as flames approached the northeastern end of the reservation.

"The fire has not come on the reservation yet," Pauma Chairman Chris Devers said. "It appears to be approaching from the northeastern area beyond the reservation boundaries and affecting the orchards" outside the reservation.

Rincon spokeswoman Nikki Symington said the tribe's firefighters were watching the fire's every move.

"Our fire chief said everything is on high alert in case the winds shift," she said.

The tribe owns Harrah's Rincon Casino and Resort, which includes a high-rise hotel. The hotel is hosting about 400 people, most of them tribal members, who were asked to leave their homes.

In Valley Center, about 1,500 evacuees filled Valley Center High School. Though were no fires were apparent in the community, people at the school kept nervous eyes on the horizon, where fires still burned on Palomar Mountain.

Patsy Roman, who said she has owned property near the high school since 1990, said she arrived at the shelter at about 4:30 a.m. Tuesday after receiving an evacuation call.

"There's food, there's water, there's a place to sleep that's safe. I have not heard one complaint," she said.

Jim Money, a shelter manager with the Red Cross, said that the shelter will remain open until the Fire Department is confident that the fires to the east will not reverse direction and enter Valley Center.

"Right now, we're just hanging in there," he said.

- Staff writer Paul Sisson contributed to this report. Contact staff writer Edward Sifuentes at (760) 740-3511 or esifuentes@nctimes.com.