Firefighters were called Tuesday afternoon to extinguish a series of blazes that broke out on the side of Interstate 5 in North Seattle after a motorhome caught fire and ignited the surrounding brush, authorities said. The fire occurred around 1 p.m. on the northbound side of I-5 near the Northgate Avenue exit, and live video from state Department of Transportation cameras showed active flames as vehicles traveled past on the freeway. Fire officials said the blaze was under control shortly before 1:30 p.m. According to a tweet by state transportation officials, the fire began when a motorhome caught fire. Authorities did not immediately say what led to the motorhome fire. No injuries were immediately reported but motorists in the area were urged to slow down.