Marine Thunderstorm Wind — Stephens Passage, Gulf of Alaska

2025-06-16 · near Cape Fanshaw, Stephens Passage, Gulf of Alaska

Event narrative

Marine Exchange wind sensors showed a sudden wind shift to the south associated with a squall line at Midway Island starting at 212pm AKDT on the 16th. These winds progressed northward with a peak gust of 50.1 knots measured at Grave Point at 245pm. The sudden wind shift caused this data to be automatically QC'd out, but was later recovered from the source agency. As the squall line reached the Port of Juneau shortly after 3pm, a cruise ship at the AJ Dock was pushed away from the shore causing the lines to snap and the ship to drift out into Gastineau Channel. The NOS Juneau Tide Gauge at the USCG dock measured a peak gust of 47mph at 306pm AKDT.

Wider weather episode

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.

View location on OpenStreetMap → (57.8364, -133.8126)

Source: NOAA Storm Events Database, event_id 1280606. Narrative written by the NWS forecast office that issued the report.