Flood — Inland Kuskokwim Delta, Alaska

2025-10-11 to 2025-10-13 · near Bethel, Inland Kuskokwim Delta, Alaska

Event narrative

This flooding was caused by storm surge moving upriver in the intertidal zone, not by runoff from heavy rainfall. Flooding extended from Napakiak northeast to Bethel. River levels in Bethel reached 9.5 ft at 3:00 PM AKDT as recorded by the local gauge datum before it experienced an outage. After the event, a high water mark survey by the Division of Geological and Geophysical Surveys (DGGS) estimated the crest at 11.01 ft. Bethel saw a barge strike the Brown Slough Bridge. The Alaska State Emergency Operations Center (SEOC) reported no obvious structural damage was observed but Bridge is closed pending an inspection. The barge was carrying 400 gallons of fuel, but no spill was observed. Images from social media showed Bridge Avenue, as well as 6th and 7th Avenue flooded. Napakiak experienced the most severe flooding in recent memory. 20 homes floated from their foundations and flooding was experienced at the store. Houses were reported floating, and the power system was flooding. 40 - 50 people were evacuated to the high school, noted the SEOC.

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 → (60.6938, -161.9982)

Source: NOAA Storm Events Database, event_id 1296159. Narrative written by the NWS forecast office that issued the report.