Flash Flood — Cumberland, Maine

2024-01-10 · near Portland, Cumberland, Maine

Event narrative

Heavy rain and snowmelt impacted Cumberland County through the early morning hours of January 10th. The rainfall totals of 2 inches and melting snow on already saturated ground led to rapid runoff of small streams and rivers along coastal watersheds. The freshwater run-off coincided with the near historical storm tide water levels not allowing for water to drain into the oceans. This interaction led to flash flooding at the time of high tide, causing numerous low lying back-bay areas to flood, along with increased urban flooding in the city of Portland as storm drains became overwhelmed. Back bay flooding was reported on Marginal Way with the closing of exit 7 off of I-295. Many businesses were flooded in the back bay area as the freshwater couldn't drain to the ocean. Additional flooding was reported on the waterfront area with storm drains also being a small contributing factor during high tide.

Wider weather episode

A powerful storm tracked northeast through the Mid Mississippi River Valley on the 9th, rapidly deepening as it approached the southern Great Lakes. Precipitation formed along and ahead of the advancing warm front, which arrived in part of northern New England during the evening of the 9th. High pressure anchored to the north of Maine dammed low level cold air up against the mountains and allowed precipitation to start as snow for most locations in western Maine, except for those east of the coastal front. The coastal front was able to quickly mix westward as heavier precipitation moved into the area, and snow changed to rain into the foothills through midnight and the early morning hours. Rain closer to the coast and snow across the higher terrain was heavy at times through the overnight hours. Snowfall of 6 to 12 inches occurred in the higher terrain, with locally higher amounts in the high peaks. Rainfall was a widespread 2 to 4 inches where precipitation remained mostly rain. A strong low level jet accompanying the deep low pressure over the eastern Great Lakes arrived during the early morning hours on the 10th, with strong to damaging wind gusts along the coast. These warm winds along with rainfall helped to melt much of the fresh snow pack that had fallen on the 7th. The strongest east southeast winds also arrived just ahead of high tide, as they were approaching their monthly spring tides. Moderate to major coastal flooding and large, battering waves occurred all along the western Maine shoreline leading to widespread damage. By the morning of the 10th, snow, rain, and wind had all moved east of the area.

View location on OpenStreetMap → (43.6712, -70.2589)

Source: NOAA Storm Events Database, event_id 1159544. Narrative written by the NWS forecast office that issued the report.