Coastal Flood — Coastal Rockingham, New Hampshire

2022-12-23 · Coastal Rockingham, New Hampshire

Event narrative

Along the Seacoast of New Hampshire, the astronomical tide was 10.3 feet MLLW at 1030 am. The storm tide reached 13.2 feet MLLW due to an accompanying 2.9 foot storm surge. Flood stage is 11.0 feet MLLW in Hampton Beach. Significant flooding occurred in Rye and Hampton where ocean waters reached the top of the seawalls as waves crashed over. Water inundated route 1A along North Beach at least 3.5 feet deep. Debris such as rocks and sand was strewn over Ocean Boulevard from strong wave action. Water was estimated to be at least five feet deep on portions of Route 1A in Hampton during the peak of the storm. Sections of Route 100 were closed as well as Route 1 on the Hampton and Hampton Falls city line as the marsh overflowed. Many water rescues were required as driver attempted to cross the flood waters or from residents trapped in their flooded homes. Cusak Avenue flooded 90 minutes prior to high tide with the city police station completely surrounded by water. In Rye, large waves moved tons of rock onto the roads that required plowing by public works to remove.

Brown's Seafood Restaurant in Seabrook was completely surrounded by water. In the community of New Castle, a seawall road was damaged, along with a historic seawall at Portsmouth Harbor Lighthouse. In Portsmouth, many roads were flooded with water nearly a foot deep at the corner of the Marcy and Water Street intersection. Mechanic Street was closed due to flooding at the intersection of Peirce Island Road. Additional flooding was reported on Walden Street, South Mill Street, Pickering Avenue, Partridge Street, Parrott Avenue, New Castle Avenue, Ceres Street and Lafayette Road. Leary Field and Haven Park flooded as storm drains backed seawater and freshwater into these low lying areas. Storm surge flood waters entered Sagamore Creek and flooded the Dinnerhorn Restaurant on Route 1 along with Geno's Chowder and Sandwich Shop.

The storm caused damage to residential and commercial buildings that only impacted the structure but also electrical systems within the buildings. Road and seawall damage was also reported across the county due to heavy erosion caused by the strong near shore waves. Many vehicles that either drove through flooded seawater or were inundated while parked experienced electrical damage. All these factors combined for significant monetary damages from this storm to both private and public infrastructure.

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 with over 120,000 customers without power.

Precipitation moved into western New Hampshire during the late evening hours of December 22, and moved across the remainder of the state by 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 that night. 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 Seacoast of New Hampshire.

Source: NOAA Storm Events Database, event_id 1069544. Narrative written by the NWS forecast office that issued the report.