Suicide Basin flood now expected to crest between 2-6 a.m. Tuesday, earlier than original forecast
- Mark Sabbatini
- Sep 15
- 4 min read
Updated: Sep 15
City planning quick repair work Monday afternoon to damaged HESCO barriers, with Mendenhall River expected to peak at about 11.7 feet
By Mark Sabbatini
Juneau Independent
Update 3:30 p.m. Monday: Residents of View Drive are being advised to evacuate their homes overnight and city workers are working to safeguard other neighborhoods near the Mendenhall River due to a glacial lake outburst flood from Suicide Basin expected to crest early Tuesday morning, officials said at a press briefing Monday afternoon.
The measures are precautionary since the forecast crest level of 11.7 feet is well below the level reached by floods in August that have set records for three straight years, said Ryan O'Shaughnessy, emergency programs manager for the City and Borough of Juneau.
"In an abundance of caution we are recommending that folks in the View Drive area evacuate their homes this evening, or just spend the night somewhere else," he said. "Again, these floods are dynamic. They take a lot of material and change the shape of the river and lake at each event, and our number-one priority is always going to be the protection of life and public safety."
People should also stay away from bridges, the levee of HESCO barriers along the Mendenhall River and areas such as Meander Way where some flooding may occur, O'Shaughnessy said.
"We can't underscore enough how much water is moving through the river at peak flow during these events," he said. "It's very, very dangerous. It will be difficult for our first responders to rescue folks, should there become a situation where somebody went into the river or otherwise."
An updated forecast issued Monday afternoon states the river is expected to crest at about 11.7 feet between 2 and 6 a.m. Tuesday, according to the National Weather Service Juneau. Nicole Ferrin, a meteorologist at the station, said during the press briefing officials will continue tracking water levels and update the forecast as necessary through the night.
Ferrin said the flood should be similar to a second annual release from Suicide Basin that occurred last October that resulted in a crest of 10.77 feet.
"One of the differences right now is we've got heavy rain coming in tonight and so the base flow of Mendenhall Lake and the river is already going to be a little bit elevated because of that," she said.
The water level in Suicide Basin was at just above 1,140 feet when the release occurred, according to U.S. Geological Survey data. The capacity level of the basin before this year’s flood on Aug. 13 was 1,371 feet.
A construction company hired by the city was scheduled to start repair work this week on some HESCO barriers damaged during this year’s record flood in August, said CBJ Public Works Director Denise Koch. But due to the new release from Suicide Basin those workers and city employees "have switched gears to do more immediate work versus a rebuild."
"The first thing that they're doing is they're refilling the HESCO barriers with additional sand and compacting those HESCO barriers," she said. "Once they're done with that then they'll start filling sandbags and they'll place sandbags along the base of the HESCO barriers, so that very first level between the HESCO barriers and the native soil is where they'll be reinforcing with sandbags."
Pumps are also being placed in the Meander Way area in a coordinated effort with the emergency operations center of the Central Council of the Tlingit and Haida Indian Tribes of Alaska, Koch said.
"We are asking people to not go and rush to Meander," she said. "We have a lot of work that's going to happen there today. We would ask for people to only go to that street if really they’re local traffic."
Officials at the briefing said no closures of city facilities or schools were planned due to the flooding.
Original story 8:45 a.m. Monday: A second glacial lake outburst flood from Suicide Basin was detected Monday morning, prompting a flood warning with the Mendenhall River expected to reach a crest of about 11.7 feet between 8 a.m. and noon on Tuesday, according to the National Weather Service Juneau.
Gauge reports indicated the release at 7:48 a.m. Monday, according to the warning. Areas expected to be affected include Mendenhall Campground, Skaters Cabin Road, View Drive, areas near the Mendenhall Glacier Visitor Center and possibly below the Back Loop Bridge.
"The outburst flood forecast is based on an estimated volume of water in the glacier dammed lake and an estimated release rate based on previous events," the warning notes. "The extent of water drainage within the basin (partial or full) can vary widely between outburst flood events and is a major source of uncertainty in the forecast, particularly with regard to the peak flood stage."
Water levels will go above the minor flood stage of about nine feet at about 10 p.m. Monday and the moderate flood stage of about 10 feet at about 2 a.m. Tuesday.
"CBJ is deploying teams with sandbags and fill material to View Drive where evacuation is advised," a bulletin issued by the City and Borough of Juneau at midday Monday states. "Residents in the surrounding area are
encouraged to monitor conditions closely and take necessary precautions."
"Please abide road and trail closures and avoid the Mendenhall River for the safety of yourself and others until further notice. The Kaxdigoowu Heen Dei/Mendenhall River Trail will be closed."
The release is far below the record flood that crested Aug. 13 at 16.65 feet. Releases from the basin have occurred annually since 2011 and weather service officials have stated more than one release annually can occur. Last year an early August release when the basin was full that crested at 15.99 fet was followed by a second release in October that crested at 10.77 feet.
• Contact Mark Sabbatini at editor@juneauindependent.com or (907) 957-2306.
