Coastal Flood — Coastal Cumberland, Maine

2022-12-23 · Coastal Cumberland, Maine

Event narrative

The morning of December 23rd had perfect alignment of a very high astronomical tide, peak storm surge of 2+ feet and large battering nearshore waves of 15 to 20 feet all coinciding at high tide. The astronomical tide in Portland was 11.3 feet MLLW at 10:16 am, already close to the established 12 foot MLLW minor flood level. The intense onshore winds produced a storm surge of 2.41 feet in Portland Harbor. The resulting storm tide topped out at 13.72 feet MLLW, it's fourth highest water level in modern history for the Forest City (records 1912-present). The tide remained above flood stage for 195 minutes (945 am - 100 pm). A temporary new tide gauge installed by the Gulf of Maine Research Institute (GMRI) in Portland Back Cove reached 13.78 feet MLLW. Across the southern tip of Maine at the relatively new Seavey Island gauge, the tide reached 12.41 feet MLLW at 1054 am with a storm surge of 2.50 feet.

Significant to major coastal flooding occurred across most vulnerable locations in Cumberland County. Significant flooding occurred along the city wharfs and side streets in Portland with inundation of up to 2 feet that included Amethyst Park, the Portland Pier, the Harbor Fish Market, Union Wharf, Widgery Wharf as well as the Custom House Wharf. Portions of Marginal Way also flooded but inundation levels were slightly less. Flooding also occurred in the Back Cove area to include the Bayside Trail, Sewage Plant Rd. and parts of Commercial Street. South Portland had flooding along Willard Beach and Bug Light State Park. The historic seawall of Fort Preble was damaged due to large battering waves. The iconic Portland Head Light was damaged as large battering waves crashed into the building which blew out windows and flooded the building in Cape Elizabeth. Additional wave damage to roads with tons of rock debris on roads that had to plowed in Cape Elizabeth. Further south, Scarborough experienced flooding on Black Point Rd. Haggis Parkway, Payne Road and sections of Route 1.

Wider weather episode

Beginning on December 22nd a powerful storm was developing over the Ohio River Valley. On December 23rd the center of the storm was deepening rapidly (974mb) as it lifted through the eastern Great Lakes. While the center tracked into southern Ontario, high pressure retreated into the Canadian Maritimes creating a strong pressure gradient across the region. Strong southerly winds developed as a result, with speeds in excess of 80 knots at around 2,000 feet. Several rounds of strong to damaging wind gusts occurred, which brought widespread power outages to the region with upwards to 240,000 customers without power.

Precipitation moved into southern Maine during the late evening hours of December 22, and moved across the remainder of the state into the early morning of December 23. Snow quickly changed over to rain on the night of December 22nd, with a changeover later in the mountains towards daybreak on December 23rd. The precipitation continued through the evening hours of December 23, then gradually ended from south to north early morning, December 24. Overland flooding was prevalent for areas where rainfall exceeded 2 inches. The impacts varied from standing water in fields to complete road washouts. The runoff exceeded capacity for most feeder creeks and rivers.

The rapidly deepening area of low pressure over the Great Lakes region combined with very high astronomical tides to produce the fourth highest storm tide ever in Portland. In addition, storm to hurricane force east to southeasterly winds occurred along the coast with nearshore waves of 15 to 20 feet coinciding during peak storm surge. Significant to major coastal damage occurred during the morning high tide cycle across the beaches and Mid-Coast of Maine.

Source: NOAA Storm Events Database, event_id 1069638. Narrative written by the NWS forecast office that issued the report.