Debris Flow — Haines Borough, Alaska

2022-10-01 · near Klukwan, Haines Borough, Alaska

Event narrative

Heavy rain was falling over the Chilkat Valley with 1 inch of rain falling in a 6 hour time frame. By Saturday morning on October 1st the Haines Police and Alaska DOT reported that a landslide came down during the overnight hours around 23 mile along the Haines Highway and blocked both lanes. It took all day for DOT to reopen the highway.

Wider weather episode

Southeast Alaska had been impacted by a number of atmospheric rivers through September to keep streamflow on small and large rivers high. Another atmospheric river lifted out of the north Pacific as the associated warm front moved over Southeast Alaska it produced heavy rain over the northern inner channels of the panhandle. The front also advected a lot of warm air with freezing levels near 10 thousand feet. The complex terrain of the region enhance the rainfall with 1.5 to 3.5 inches of rain fell over a 12 to 18 hour period.

The heavy rain and significant ice melt from the very warm temperatures in the headwaters of the Taiya River produced a lot of overland flow. This caused moderate flooding along the Taiya River from the early morning hours to the late afternoon on October 1st. There was road closures, damage to National Park Service infrastructure along the Chilkoot trail and near the Dyea campground. This was also the 4th highest peak flood on record. There was also moderate flooding along Jordan Creek in Juneau from the early morning to the afternoon hours on October 1st. The crested was the 2nd highest peak flood on record. A large landslide along the Haines Highway around 23 mile that came down in the overnight hours of October 1st and blocked the road. The area around the landslide reported 1 to 1.5 inches of rain in 12 hours.

View location on OpenStreetMap → (59.4145, -135.9190)

Source: NOAA Storm Events Database, event_id 1061468. Narrative written by the NWS forecast office that issued the report.