(Troutdale, OR) -- The December storms caused the Sandy River to change its course. The Multnomah County Sheriff's office is warning that between Oxbow Regional Park and Dabney State Recreation Area, the change in the river's flow has caused fallen trees to clog the river. There's now an area of small rapids that could pull people floating the river into submerged trees, causing them to get stuck. Online satellite images haven't updated and don't show the change. Warning signs have been posted. River users should wear lifejackets, carry a whistle, and a light if you plan to be on the water near dawn or dusk.