Flash Flood — Oxford, Maine

2023-12-18 to 2023-12-19 · near Gilead, Oxford, Maine

Event narrative

Major flooding occurred on the Wild River in Gilead with the USGS river gage marked the 2nd highest crest on record of 16.4 feet. The gage was established in 1960 and the only flood of higher flows was that following Irene in 2011. The streamflow was near 34 kcfs, which falls between a 0.5 and 0.2% annual chance exceedance level, otherwise referred to as a 200 to 500 year flood. The flooding was the result of 5 to 6 inches of rainfall and 3 to 4 inches of snowmelt running off within an 18-hour timeframe. The steep slopes of the Wild River combined with frozen ground resulted in a fast rise of 13 feet in 12 hours. The fast-moving water overtook Route 113 and washed out a 80-foot section. The flows from the Wild River contributed to the Androscoggin River major flooding in downstream Bethel.

Wider weather episode

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.

View location on OpenStreetMap → (44.4000, -70.9800)

Source: NOAA Storm Events Database, event_id 1151034. Narrative written by the NWS forecast office that issued the report.