Marine Thunderstorm Wind · Gulf of Alaska

Marine Exchange wind sensor at Rocky Island, at the intersection of Icy Strait, Chatham Strait, and Southern Lynn Canal, showed a sudden wind shift from strong northerly to the south associated with a squall line. The peak gust of 49mph was measured at 317pm AKDT. The Sisters Island NWS sensor measured a peak gust of 47mph in the same hour. These winds progressed northward into Lynn Canal. The sudden wind shift caused some of the data to be automatically QC'd out, but was later recovered from the source agency.

On the afternoon of Monday, June 16th, 2025, a fast-moving squall line of thunderstorms tracked northward across the central and northern Panhandle, resulting in damaging wind gusts and localized impacts, particularly in the Juneau area.

Analysis indicates that the primary storm structure was a squall line. The squall line stretched across the panhandle and the Inside Passage east to west, beginning sub-severe in the vicinity of Wrangell around noon, reaching severe criteria as it tracked up Stephen's Passage, then continued northward, reaching Skagway shortly after 5pm.

As the squall line reached the City and Borough of Juneau just after 3pm, a sudden onset of high winds of 50+ mph led to multiple damage reports across the area. The most significant incident occurred at the AJ Dock, where mooring lines securing a cruise ship snapped, causing the vessel to drift from the dock. Additional impacts across Juneau included broken tree limbs, shattered vehicle windshields, and temporary power outages.

Near the Juneau International Airport, a gustnado was also observed crossing Egan Drive and the airport parking lot. After reviewing satellite imagery, eyewitness reports, and surface observations, the NWS has confirmed the occurrence of a gustnado in the vicinity of the airport and is categorized as a thunderstorm wind event event within the severe squall line.