Boaters, beware. The MD Natural Resources Police has issued an advisory on the Upper Potomac River, including its tributaries, through April 3. Due to recent rainfall, river levels are hazardous to recreational boaters and should be avoided at all cost. This means that despite the nicer temps, please save the non-whitewater boating until this weekend. Swimmers should also be cautioned. There are treacherous currents, dramatic wave action, and an increased amount of both visible and and invisible debris (beneath the surface). Professionally-guided river rafting trips are not included in the advisory. The advisory is in effect through Thursday, April 3, when information will be updated. Be careful out there.