Scene from a hay bale fire in North County. (Photo courtesy San Diego Fire Department)Scene from a hay bale fire in North County. (Photo courtesy San Diego Fire Department)

Fire crews were working a blaze that consumed hundreds of bales of hay in an open field across from the San Diego Zoo Safari Park on Sunday morning, the San Diego Fire-Rescue Department said.

Firefighters say they are expected to be on the scene throughout the day.

Crews responded at 11:20 p.m. Saturday to the location of the field near the 15000 block of Old Milky Way near San Pasqual Valley Road and worked throughout the night.

Eight fire engines, four brush rigs, a water tender, a battalion chief and other units were joined by Cal Fire dozers in battling the fire, which was still smoldering as of Sunday morning. Crews said that it has been hard to get to the fires because they were still smoldering inside rolls and stacks of hay.

The fire department added that smoke might still be visible in the area.

The cause of the fire was unclear.

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