Alaska declares state disaster emergency as Mendenhall River floods

Severe flooding caused by a glacial lake outburst has led to a state disaster emergency declaration in Alaska on Tuesday, August 6, 2024, with the Mendenhall River cresting at 4.87 m (15.99 feet) and inundating north Juneau’s neighborhoods.

Alaska Governor Mike Dunleavy declared a state disaster emergency on Tuesday, August 6, as the Mendenhall River reached record levels and flooded neighborhoods in Mendenhall Valley. The flooding was caused by glacial lake outburst that occurred upstream in the Suicide Basin and Mendenhall Glacier.

The outburst led to the Mendenhall River cresting at 4.87 m (15.99 feet) at 03:15 local time (LT), according to the National Weather Service (NWS), surpassing the major flood stage of 4.27 m (14 feet). The rapid inflow of water caused Mendenhall Lake to rise nearly 3.05 m (10 feet), causing severe flooding in the area.

The flooding caused extensive property damage, displacing many residents in north Juneau’s neighborhoods. Photos of the affected areas show homes turned into islands, submerged driveways and roads, and vehicles with floodwater reaching the windshields. The City and Borough of Juneau issued an evacuation order on the night of August 5 and set up an emergency shelter for displaced residents.

At least 100 homes were damaged in what has become a recurring hazard for neighborhoods near Mendenhall Lake and River. The damage from this year’s flooding was widespread, with streets experiencing 0.91 – 1.22 m (3 – 4 feet) of water in some areas, according to local authorities.

“I would say over a hundred homes right now,” said Deputy City Manager Robert Barr. “There was a lot more water in the valley, on the streets, in people’s homes,” he added. However, less erosion was reported compared to last year.

No injuries have been reported. More than 20 people sought refuge at the emergency shelter by 03:00 LT Tuesday, with over 30 people present by 06:00 LT. The shelter is expected to remain open through the afternoon.

The Alaska Division of Homeland Security and Emergency Management reported no deaths or injuries from the flooding. “I am grateful no one has been injured or killed by this morning’s outburst flood,” said Governor Dunleavy.

The City and Borough of Juneau worked with Capital City Fire/Rescue and the Juneau Police Department to issue voluntary evacuation orders.

The National Weather Service said that the river level was dropping and was measured at nearly 3.66 m (12 feet) by late Tuesday morning. Residents along the river were strongly advised to evacuate, with the city sending a text alert just before 19:00 on August 5.

The Alaska Department of Environmental Conservation advised residents to secure their heating oil tanks to prevent pollution from swept-away tanks. Alaska Electric Light and Power cut power to affected areas as a precaution, and Juneau Animal Rescue offered emergency boarding for pets.

Senator Lisa Murkowski communicated with local authorities about the damage, and the Juneau Assembly scheduled a special meeting to discuss the local emergency and request state and federal assistance.

The Mendenhall Campground was evacuated, and low-lying areas were flooded with water. Roads and trails, including the Diamond Park Pedestrian Bridge and the Airport Dike Trail, were closed due to flooding. Residents were encouraged to limit vehicle traffic to facilitate evacuations and emergency response.

References:

¹ Alaska declares state disaster emergency as ‘glacial lake outburst’ floods homes, roads – FOX Weather – August 6, 2024

² Annual glacial outburst flooding affects Juneau’s Mendenhall Valley – Alaska Public Media – August 6, 2024

³ Picturesque glacier releases water down a river in Alaska. More than 100 homes are damaged – AP – August 7, 2024

Rishav Kothari

I am an Assistant Editor and Severe Weather & Science Journalist at The Watchers, specializing in real-time severe weather coverage, geophysical event reporting, and research-driven scientific analysis. You can reach me at rishav(at)watchers(.)news.

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