Flood — Franklin, Vermont

2018-01-13 to 2018-01-14 · near Swanton, Franklin, Vermont

Event narrative

A large ice jam formed on the Missisquoi River in the Village of Swanton, VT, extending from below the Route 78 bridge upstream for several miles. Numerous structures were impacted with dozens of homes evacuated. State Route 78 was closed for nearly 24 hours due to high water. Several of the impacted homes were heavily damaged.

Wider weather episode

A very deep upper level trough from Central Canada to the Gulf of Mexico allowed for a warm, moist flow with temperatures in the 50s and 60s through the early evening hours of January 12th across VT. An arctic front moved across VT during the night with temperatures by Saturday morning (January 13th) in the teens and 20s and falling throughout the day. In addition low pressure traveled along the front as it moved across Vermont delivering an inch or more of precipitation in the form of rain, freezing rain, sleet and snow.

Several impacts occurred with this event. First, temperatures 25 to 30 degrees above normal caused significant snow melt across the region and then an inch or more of rainfall in January 12th lead to rivers approaching bankfull with several reports of flooding due to ice jams. Some of these rivers included the Winooski near Montpelier Jct, Lamoille at Johnson, Passumpsic near Lyndonville, Missisquoi near Swanton and the Connecticut river near Windsor.

Second, rapidly falling temperatures overnight into Saturday morning accounted for rain changing to freezing rain, sleet then snow. Significant sleet occurred in the Champlain Valley and much of central VT with 4 to 8 inches of snow as well across northwest VT. Sharply falling temperatures allowed for a flash freeze of area roads making for extremely hazardous travel.

Third, the combination of earlier thawing and sub-zero temperatures allowed for freeze-up jams to develop and exasperate on-going problems on the Missisquoi and Lamoille rivers.

View location on OpenStreetMap → (44.8968, -73.1175)

Source: NOAA Storm Events Database, event_id 733131. Narrative written by the NWS forecast office that issued the report.