KINY radio in Juneau (http://is.gd/faoSM3) says the National Weather Service has issued a flood watch for Mendenhall Lake and Mendenhall River.
The watch, which means conditions are favorable for flooding, will remain in effect through Friday afternoon.
The rising water is due to a glacial dam release in the vicinity of Suicide Basin. The Civil Air Patrol confirmed the filling of the Suicide Basin Glacier Dam in a flight about a couple weeks ago.
According to KATH-TV, an NBC affilate in Juneau, the Mendenhall Lake level was observed at 6.66ft, up from a normal level of around 5ft, Thursday morning.
The lake is expected to crest at about 9.5ft in the early hours of Friday. Flood stage for the lake is 9ft.