1994 Koyukuk River Flooding
Overview
August 1994 brought heavy rains and wide scale flooding to the Koyukuk River basin. The Koyukuk, Kobuk and Noatak rivers all flooded, with the Koyukuk experiencing the most severe flooding. More than 300 people along the Koyukuk were displaced. Approximately 100 homes experienced damage and 38 more were completely destroyed. The communities of Allakaket, Alatna and Hughes were especially hard hit. A portion of Allakaket relocated to higher ground after the flooding. At Hughes, the peak discharge was estimated at 330,000 cubic feet per second which on an annual basis has only a 1% chance of occurring. For many residents the flooding was the worst in living memory.
Weather woes
Flooding along the Yukon and Koyukuk Rivers is often linked to snowmelt and river ice breakup. Less commonly, flooding results from extreme summer rainfall, as seen in 1994. During the month of August, there were two significant periods of rain. August 15-18 brought 2-5 inches of rain, causing the Koyukuk River to rise 10 ft. Another round of rain from August 24-27 produced 3-5 inches. Even though the rainfall totals were similar in both periods, by the time of the second event in late August, the ground was saturated and the rivers were already at bankfull triggering severe flooding.
Disaster declared
Aug. 26: Governor Hickel declared state disaster emergencies for Kobuk, Kiana and Kotzebue
Aug. 28: Allakaket and Alatna evacuated
Aug. 31: Hughes evacuated
Sept. 13: President Clinton signed federal disaster declaration
Total costs of $70 million (in 1995 dollars) estimated as a result of the flooding, temporary housing, evacuations, and damages
Community specific impacts
Allakaket, Alatna and Hughes are located along the Koyukuk River and experienced the most damage during the August 1994 flooding. All three communities were evacuated. Many residents spent the winter elsewhere until rebuilding occurred in 1995. Floodwaters in Allakaket, were up to 10 ft deep, 17 homes were destroyed, 24 suffered major damage, and 16 suffered minor damage. In Alatna, the floodwaters were 8 ft deep with some locations flooded by more than 10 ft. All the homes in Alatna, except one on the north edge of town, flooded. In addition, many structures floated off their foundations. Several homes and the community center came to rest 4 miles downstream after the water receded. In Hughes, flooding between 4-6 ft deep was recorded in the center and northern parts of town, 22 of 29 occupied homes were destroyed.
Relocation
Allakaket and Alatna relocated as a result of the flooding. In Allakaket, a portion of the town moved 2 miles inland and uphill to higher ground. In Alatna, FEMA and the state of Alaska helped the community rebuild on higher ground near the original site, but above the 1994 flood levels. The new site of Alatna is outside of the Allakaket city boundaries.