California's worst drought in a century is devastating the state's agriculture and destroying its forestland, which is being consumed by wildfire, Governor Jerry Brown said Friday as he declared a state emergency. The emergency declaration allows California to access federal help to battle the drought, which has left huge swathes of tinder-dry forest vulnerable to catching fire. On Thursday, a massive blaze raged just outside Los Angeles, damaging several homes and forcing residents to evacuate the area, where the fire risk had been elevated for weeks. Brown urged residents of his state to reduce their water use by at least 20 percent. "I've declared this emergency and I'm calling on all Californians to conserve water in every way possible," he said in his statement. "We can't make it rain," he added. "But we can be much better prepared for the terrible consequences that California's drought now threatens, including dramatically less water for our farms and communities, and increased fires in both urban and rural areas." Brown told reporters in San Francisco that the current conditions were "the worst drought that California has ever seen since records (began) about 100 years ago," media reports said. The region is suffering its third dry winter in a row, highlighted by the Los Angeles blaze. California and other western U.S. states are routinely hit with wildfires during the summer, but winter fires like the ones currently raging, are relatively rare. California's rivers and reservoirs have reached record lows, with only 20 percent of the normal average supplies of water from melting snowpack, which flows down from mountains like the Sierra Nevada north-to-south range.