An ice jam on the Winooski River has prompted officials to warn residents about potential flooding in Montpelier. The Montpelier Emergency Management Team was monitoring a significant rise in water levels in the river’s north branch by Langdon Street on Sunday. Building cellars along Main and Langdon streets have been flooded or are at risk of flooding, officials said. Emergency officials warned residents and business owners not to go into basements that are flooded and have live electrical power. Further north in Essex, police said North Williston Road and portions of Vermont Route 128 are closed because of flooding from the Winooski River.