Impacts of Post-tropical Storm Noel (November, 2007) on the Atlantic coastline of Nova Scotia

Observations of coastal infrastructure and detailed surveys of physical changes at eight beaches document the impacts of Post-tropical Storm Noel that struck the Atlantic coast of Nova Scotia on November 3-4, 2007. The surveys were part of an ongoinginvestigation of the impacts of major storms on different shore types and their rate of recovery. In addition, flood water levels and wave run-up extent were documented to better define shores vulnerable to these coastal hazards. The area of gale to storm force southerly to southwesterly winds inNoel extended along most of the Atlantic coast of Nova Scotia. Waves in excess of 8 m height lasted nearly 6 hours, with a focused direction of 190-220 degrees as they peaked in height. Wave set-up increased water level but it was still about 50 cm less than maximum levels reached during HurricaneJuan. If Noel had occurred a week earlier during spring tides, the damage probably would have been significantly greater in area, and possibly in intensity. Power outages and minor damage from waves tossing debris and rocks across adjacent roads and properties occurred in similar locations as paststorms. No official dollar values have been published for the cost of Noel. The worst damage to infrastructure was on the outer coast, in the vicinity of the Lahave River, at Peggy's Cove and scattered locations along St. Margarets Bay. Waves overwashed all shores less than 4.4 m elevation.Backshore dunes were flooded a maximum distance of 84 m from the beach. A low gravel barrier beach crest was pushed nearly 6 m landward and its lagoon shore was extended 10 m. Where backshores were higher, wave run-up extended to elevations of 6 m across vegetated sand dunes and possibly as high as12 m across bedrock shores. Flood waters reached 1.9 to 2.3 m elevation at lagoons and estuaries along the Eastern Shore and possibly as high as 3.1 m along the South Shore. Most of the beaches still retained their maximum sediment build-up when Noel struck which lessened the wave impacts. Naturaldunes were cut back less than 7 m, except where water was funneled through existing dune cuts used as trails, or water turbulence was intensified around artificial structures, such as boardwalks and fences. Channels were cut through weak parts of dunes at Lawrencetown, Martinique and Cherry Hillbeaches. A backshore pond along Hartling Bay was completely drained and became tidal when the barrier beach fronting it was breached. The Atlantic coast of Nova Scotia has been retreating landward for thousands of years because of sea level rise. Storms such as Noel cause one small step in thatprocess which varies in intensity depending on the condition of specific shores. For the eight beaches investigated Cherry Hill and Cow Bay continue to rapidly evolve, parts of Lawrencetown and Martinique beaches are now more susceptible to rapid change, Hirtles and Miseners-Long beaches continue toslowly migrate, Conrads Beach is in a phase of building and less impacted, and natural movement of Crescent Beach became more constrained with the addition of rock in response to dune erosion caused by Noel.