Central Vermont Railroad at Montpelier Junction, 1927

Montpelier is susceptible to flooding at all times of the year, but particularly during the spring run-off and ice break-up. Floods have occurred due to intense rain, ice jams, and combinations of the two. Ice jams usually form in the spring when thick ice breaks up and clogs the river channel. Flood stages during an ice jam can increase very rapidly, from feet per minute to feet per hour. In some instances, communities have as little as 1 hour of lead time between the time an ice jam forms and the start of flooding.

The most destructive hydrological event in Vermont's history, a tropical storm dropped nearly 8 inches of rain on Montpelier in 24 hours. In the Winooski Valley, 55 deaths and $13.5 million in damage occurred. The flood destroyed many bridges and caused extensive structural damage to buildings.

Heavy rains and moderate temperatures contributed to a large amount of run-off. Coupled with the break-up of thick ice, flooding occurred in downtown after an ice-jam formed on the Winooski behind the old Bailey Dam.

Due to sudden warm temperatures, the ice broke up and an ice jam occurred at 7 AM just beyond the Bailey Avenue bridge. The water level rose quickly, and by 8 AM most of Montpelier's downtown area was flooded. Even after the water level dropped, damage related to the flooding continued as cold weather caused freezing of wet objects. A total of 62 towns in Vermont and New Hampshire had ice jam flooding problems that spring.