Storms may hit wildfires with much-needed rain (AP) CHEYENNE, Wyo. - The real possibility of significant rain - finally - could give a much-needed break to firefighters battling enormous wildfires up and down the Rocky Mountains. Forecasters in Colorado, Wyoming and Montana say there's a chance for strong thunderstorms across the region Thursday and in the days ahead. Heavy rain could make a big difference against wildfires, including one that has burned nearly 400 square miles of ranchland in southeast Montana. Firefighters also are optimistic about rainfall stifling a fire that forced the evacuation of dozens of forest cabins in southeast Wyoming, and a fire perilously close to the town of Newcastle in northeast Wyoming. Rain helped firefighters at the 16-square-mile Squirrel Creek fire about 30 miles southwest of Laramie. About 15 homes were evacuated Wednesday but they could be allowed back Thursday. An unknown number of other evacuees were able to return. Thunderstorms aren't always good news for firefighters in the West. They worry that gusty winds and lightning could make their job more difficult. Light rains that fell early Wednesday helped calm Colorado's Waldo Canyon Fire, which has scorched 28 square miles, killed two and destroyed almost 350 homes. Firefighters predicted full containment of the fire Friday, with more rain, cooler temperatures and higher humidity predicted through the weekend. Authorities are still investigating how the fire started. On Thursday the El Paso County sheriff's office announced that investigators have pinpointed where the fire started but didn't disclose the location. Colorado officials called off holiday displays from Fort Collins to Colorado Springs, while law enforcement warned of hefty fines for people caught violating personal fireworks bans. Some of those fires: Montana: Fire officials have begun jointly managing five large southeastern wildfires so they can quickly move personnel and equipment where they're needed. That includes the Ash Creek Fire, which is the state's largest at 382 square miles. It's 50 percent contained. Firefighters on the Powerline Fire contained a late-afternoon run of 600 acres, nearly 1 square mile, on Wednesday. Utah: Nine major wildfires were burning across the state, including the Shingle fire that has burned 8,200 acres and threatened 550 cabins or summer homes and 300 other structures in Dixie National Forest, about 30 miles southeast of Cedar City, officials said. The Quail Fire in Alpine has scorched more than 3 square miles and destroyed one barn. About 325 homes were evacuated but some people were allowed to return Wednesday.