NEW : Several people reported missing , police say . Firefighters from the U.S. and Canada rush to fight the blaze . Flames climb stories high into the sky and spread to Canada . The video appears to reveal an explosion . Water spills into the river just past the fire .
NEW : Several people reported missing , police say . Firefighters from the U.S. and Canada rush to fight the blaze . Flames climb stories high into the sky and spread to Canada . Water spills into the river just past the fire .