A grass fire razed more than 150 acres near West Elkhorn Boulevard and Power Line Road late Monday morning, with winds sending smoke into downtown Sacramento, according to the Sacramento Fire Department. As of 1:15 p.m., crews had extinguished the bulk of the fire, the Sacramento Fire Department said. About 70 firefighters responded to the blaze at 11:13 a.m., making a stop at West Elkhorn Boulevard to prevent the fire from jumping the road, said Capt. Keith Wade, spokesman for the Fire Department. The fire progressed northward, he said. A Sacramento Metropolitan Fire District helicopter made water drops on that end of the fire. Wade said there were a number of hay bales north of the fire that could become fuel. The cause of the fire is still unknown and no structures were threatened, he said. Smoke from the fire was wafting near the Sacramento International Airport and farther south into the city. Airport operations were not affected, said Laurie Slothower, spokeswoman for the airport. The fire is estimated to have reached 156 acres. Crews have extinguished the bulk of the fire, the Sacramento Fire Department said.