Winter Storm — Southern Carroll, New Hampshire

2025-12-29 · Southern Carroll, New Hampshire

Event narrative

Precipitation began in the very early morning hours on the 29th, and began mainly as freezing rain except for a few spots that started as snow. The freezing rain was heaviest and accumulated most rapidly through the morning hours. It was around this time that trees and wires began to come down. Power outages also increased through the morning hours, peaking between 10 and 20 percent outage rates. Precipitation, mainly freezing rain and rain, continued into the mid afternoon hours on the 29th before coming to an end. Flat ice accumulations over the Lakes Region into the southern White Mountains were generally in the 0.33 to 0.5 inch range, with locally higher amounts approaching 0.75 inches.

Wider weather episode

Early on the 28th a strong low pressure system crossed the Great Lakes into southern Ontario and Quebec. Upper level support for this low pressure remained strong, and prevented secondary low pressure from forming until the occluded front was approaching the Bay of Fundy. As precipitation approached the region, very cold air was in place and lingering surface high pressure helped to hold it in place. Additional cooling through evaporation resulted in a robust interior cold air dam, while the lack of a strong anchoring high pressure allowed the coast to start as freezing rain but it quickly warmed up above freezing. Strong forcing aloft pushed warm air well north and made for a quick transition from any snow to sleet and freezing rain. Mixed precipitation began on the evening of the 28th and continued through the evening on the 29th. The lack of reinforcing cold air damming allowed temperatures to creep towards freezing even in the colder areas, and prevented significant ice accumulations over a more widespread area. Precipitation slowly tapered off on the evening of the 29th and even ended as some additional freezing rain and drizzle in places that had warmed up. Key messages: ice storm, power outages, travel accidents.

Source: NOAA Storm Events Database, event_id 1300565. Narrative written by the NWS forecast office that issued the report.