A lull in hot, dry winds that had fueled a deadly southern California wildfire gave firefighters a break on Saturday, but they warned residents to remain wary of the deadly, unpredictable blaze, Reuters reported. The arson fire near Palm Springs has killed four firefighters and injured six and consumed 39,900 acres (16,150 hectares). Fire crews have managed to contain 40 percent of it in the rugged and brush-choked terrain, despite seasonal Santa Ana winds that gusted to 45 miles per hour (72 kph). By morning, the huge plume of dark brown smoke over the mountains had diminished significantly, winds had calmed and firefighters were strengthening their containment lines. One of the injured men remained on life support with burns over 90 percent of his body. The reward for information about the arsonists who caused the blaze had risen to $500,000. Fire crews who had spent the night battling the inferno near where the firefighters died said the area was desolated, but some homes had been saved. "As we were driving through the area, it was pretty much a moonscape. We encountered a lot of structures that had been lost and some good saves," said Jason Hosea from the City of Long Beach fire department, who had just been relieved after a night on the fire lines. "We knew what the situation was prior to being deployed. All of our crews had an extra sense that it was dangerous." California Department of Forestry spokesman Joel Vela said Saturday was a pivotal day. "We are trying to take advantage of the lull in the weather to improve all containment lines and make contingency plans," he said at the fire command center in Beaumont. Firefighters said the key to some houses' survival was whether their owners had cleared brush. "Unfortunately, the firefighters that died were in an area completely surrounded by brush that hadn't been cleared from the home," said Moe Sinsley, a Long Beach battalion chief, who also had just left the fire lines. Vela said firefighters worried that the shift in the winds could intensify a different part of the fire and send it running in a different direction. The fire's western flank is about a mile from the small city of San Jacinto. "That's why we are very, very skeptical and we are being very, very cautious," he said. Vela said some of the 700 residents who fled 30-foot (9-metre) walls of flame on Thursday would be escorted home to survey damage, but likely would not be allowed to stay. At least 10 houses had been destroyed. The blaze has yet to wreak the destruction wildfires in October 2003, which burned for days outside Los Angeles and near San Diego, killing 24 people, destroying more than 3,000 homes and burning some 740,000 acres (300,000 hectares).