The Montana Department of Agriculture has announced a temporary closure of Beaver Lake in northwestern Montana to watercraft after finding an invasive weed has grown tall enough to get caught on boats, increasing the chance it could spread to other water bodies.
The agency on Wednesday announced the closure after learning a patch of Eurasian milfoil discovered last fall had spread to a larger area and individual weeds had been found in other sites.
Officials plan to operate a diver-dredge to suck up invasive weeds later this week.
Department Weed Coordinator Dave Burch says that the closure could be lifted in about a week. The lake remains open to anglers and swimmers.
Milfoil usually grows in water less than 20 feet deep.