Flood in Kennebec County, Maine

On December 19th, the Kennebec River at Hallowell reached major flood stage, cresting at 22.5 feet at the USGS river gage. There was significant damage to riverside businesses with floodwaters reaching all the way up to Route 201 on Water Street. Flood waters filled basements and were up to 18 in over 2 dozen businesses in downtown Hallowell. Further downstream in Gardiner there was severe flooding near the confluence with the Cobbosseecontee Stream and the Kennebec River between Route 201, Bridge Street, and Water Street. Dozens of businesses and apartments were inundated with water up to 5 feet deep.

Low pressure began organizing in the Gulf of Mexico on the 16th, setting record low sea level pressures as it traversed the Southeast through the 17th. Strong high pressure over the North Atlantic created a deep southeasterly flow that drew warm air into New England ahead of the approaching storm. By the time precipitation arrived on the evening of the 17th, temperatures were warm enough for rain everywhere except the highest peaks. Early on the 18th a shortwave trough was approaching from the Great Lakes and led to rapid deepening of the low pressure as it paralleled the Eastern Seaboard. Even as the center of the storm remained near Chesapeake Bay on the morning of the 18th, a strong low level jet had developed and winds began to gust in excess of 50 mph well inland from the coast. Damaging wind gusts continued into the afternoon. Hundreds of thousands of customers lost power due to falling limbs and downed wires. The anomalously warm air mass also led to intense rainfall rates beginning on the evening of the 17th, which continued into the 18th. Upsloping winds also enhanced precipitation along the southeast facing slopes of the mountains. Widespread 3 to 4 inches of rain fell, with isolated pockets of 6 to 8 inches. This fell on top of snow that was ripe from previous rainfall about a week earlier. An additional 2 to 3 inches of snow water equivalent was likely added to rainfall runoff. Numerous road washouts and road closures occurred due to flash flooding and fast responding small stream and tributaries. Widespread moderate to major flooding occurred along mainstem rivers. The storm destroyed 13 homes, caused major damage to 106 others, with an additional 65 homes receiving minor flood damage. Private damage was in the millions with public infrastructure damage of 20+ million being reported by FEMA.