Flood — Kuskokwim Delta Coast and Nunivak Island, Alaska

2025-10-11 to 2025-10-13 · near Quinhagak, Kuskokwim Delta Coast and Nunivak Island, Alaska

Event narrative

This flooding was not caused by heavy rain, but by storm surge moving up along the Kuskokwim River into the intertidal zone. The community of Tuntutuliak experienced major flooding due to the surge flowing up into the Kuskokwim River channel, with the worst flooding observed near the time of normal high tide on the morning of October 12th. Based on early high water survey data conducted by the Department of Geological and Geophysical Survey, water levels reached several feet above the normal high tide height in Tuntutuliak, similar to what was observed father upstream along the Kuskokwim River. The Alaska State Emergency Operations Center (SEOC) reported that multiple homes were moved from their foundations by water and that an unknown volume of waste oil was spilled from a service station in the community as a result of the water inundation.

Wider weather episode

The remnants of Typhoon Halong in the northern Pacific Ocean began approaching the Bering Sea on Saturday, October 11, 2025, as they merged with a deep upper-level low east of Russia's Kamchatka Peninsula. As the systems merged and underwent extratropical transition, the resulting storm was forced northward by a blocking high-pressure ridge over the Gulf of Alaska. Subsequently, the storm's strength increased rapidly as the surface low was steered north toward the western Alaska coastline. Halong's remnants tracked quickly northeast from the Central Aleutians on October 11, across the Seward Peninsula as a hurricane-strength low on October 12, then weakened over the Beaufort Sea early on October 13.

Impacts were first observed across the Pribilof Islands on the evening of October 11, where wind gusts reached 91 MPH as the storm center passed to the west. As the system intensified and moved northeast, it produced widespread damaging winds across the Yukon'Kuskokwim Delta and north through the Brooks Range, with gusts exceeding 100 MPH in some communities. Simultaneously, intense onshore flow drove a record-breaking storm surge into the Yukon'Kuskokwim Delta coast, resulting in catastrophic flooding and destruction across communities from Kongiganak to Hooper Bay.

After reaching a minimum central pressure of 960 millibars (MB) early on October 12, the storm gradually weakened as it tracked northeast, producing additional wind and surge damage across eastern Norton Sound and Kotzebue Sound before dissipating over the Beaufort Sea on Monday, October 13.

What made Ex-Typhoon Halong particularly unusual was fourfold:

1. A long and unobstructed southwesterly storm track;

2. The timing of its rapid intensification as it approached the coastline;

3. The onshore orientation and extreme intensity of its wind field across the Yukon'Kuskokwim Delta and areas north; and

4. The storm's coincidence with the astronomical high tide, which greatly amplified coastal flooding.

In addition, there was no sea ice present in the Bering or Chukchi Seas, leaving the coastline highly vulnerable to wind-driven waves and surge. Collectively, these factors made Ex-Typhoon Halong one of the most significant coastal storms to impact western Alaska in recorded history. In terms of wind energy and coastal inundation, the storm's intensity and effects were comparable to those of a strong Category 2 hurricane.

View location on OpenStreetMap → (60.2659, -162.5969)

Source: NOAA Storm Events Database, event_id 1296161. Narrative written by the NWS forecast office that issued the report.