Threatened with potential flooding, Vermont's capital maintained its watch on the frozen Winooski River on Thursday, with officials saying the risk had reached its highest point yet.
Fed by rain, melting snow and disintegrating ice, the river was rising but was still eight feet below flood stage at 8:30 a.m.
A flood watch issued by the National Weather Service was in effect through Thursday afternoon, and city officials warned that the thawing of the river's ice was at a critical juncture.
"The situation could change at any time and the flood hazard is at its highest point to date, so residents are strongly urged to monitor conditions and tune into radio and TV broadcasts for weather and flood updates," the city said in an advisory.
For weeks, the capital has been on edge, fearing a repeat of a March 11, 1992 flood caused by an ice jam on the river. Vermont National Guard members have filled and distributed thousands of sand bags, and city officials have warned residents to prepare for the worst.
The threat was exacerbated Wednesday night as temperatures climbed into the mid-50s and rainfall, but city officials said the ice in the river wasn't breaking up and that no flooding was imminent.
"The good news at this time is that the sheet ice on the river (upstream of the freeze up jam or channel obstruction) has not begun to break up and is not yet showing the type of cracking that indicates that break up is imminent," said City Manager William Fraser. "The bad news is that the rain is steady and predicted to continue to midday and the river level has been steadily rising."
The National Weather Service has issued a flood advisory for all of Vermont.
"The snow melt combined with up to a third of an inch of rainfall will cause some sharp rises on area rivers today," the Weather Service said. "The rises could be sufficient to break up the solid ice cover and ice jams may result."
A cold front was moving in and expected to drop temperatures below freezing late Thursday, arresting some of the thawing.
Montpelier wasn't the only place with trouble. The Mad River in Moretown overflowed its banks Thursday morning because of an ice jam, forcing volunteer firefighters to evacuate one house and rescue a woman who tried to drive her Subaru through a flooded road.
"It's going to get worse," said Fire Chief George Moulton. "We're looking at another hour of rain. It's come up 4 feet since 5 this morning."