Flash Flood — Belknap, New Hampshire

2023-07-29 · near Alton, Belknap, New Hampshire

Event narrative

Heavy rain caused a washout on Avery Hill Road due to rushing water off steep terrain.

Wider weather episode

A stalled frontal boundary and surface low pressure began to slowly lift northward into the southeast New Hampshire through the Midcoast of Maine on the afternoon of the 29th. Showers and thunderstorms developed along the boundary and moved eastward. Since the system as a whole showed very little forward progression, multiple rounds of showers and thunderstorms ended up moving across the same locations multiple times, on top of already saturated soils. This ended up leading to multiple instances of flash flooding, specifically near the coastal counties. A few isolated reports of severe hail were also reported.

View location on OpenStreetMap → (43.4500, -71.2997)

Source: NOAA Storm Events Database, event_id 1124073. Narrative written by the NWS forecast office that issued the report.