Thunderstorm Wind in Carroll County, New Hampshire

The first microburst occurred over the open water of Lake Winnipesaukee shortly after 4:00 PM on June 18th. Based on damage reports this likely occurred in the vicinity of Round and Welch Islands in Gilford, New Hampshire. There were pictures of trees snapped on Round Island and reported damage on parts of Welch Island. The microburst continued unimpeded by friction towards Sandy and Cow Islands in Tuftonboro, New Hampshire. There were at least three camps damaged by tree falls on Sandy Island. On the southwest side of Cow Island there was significant tree damage. At least three additional camps were damaged by falling trees, as well as at least two docks that sustained damage. An estimated 1,500 trees, mostly softwood, were either snapped or uprooted by the winds. The open water and lack of friction likely allowed this microburst to expand beyond on the accepted definition of areal extent.

An unseasonably strong mid-level shortwave trough progressed across Northern New England on June 18th. This brought deep layer shear that allowed for high potential storm structure organization into line segments. The forcing combined with deep moisture allowed for robust convection, with bowing line segments transiting across Central and Southern New Hampshire. Convective wind gusts along with a few areas of microburst wind damage brought down 1000s of trees.