Water is still rising in Suicide Basin on the Mendenhall Glacier, but if or when it will release isn’t predictable.
Suicide Basin is a natural collector of rainfall and snowmelt, and is dammed by the glacier. The dam has broken the last three summers, causing various levels of flooding on Mendenhall Lake and Mendenhall River.
The National Weather Service said on Friday that a visual check of the basin indicates the amount of water already exceeds 2012 levels when the dam released, and a jökulhlaup could happen at any time.
Jökulhlaup is the Icelandic name for a glacial outburst flood. According to the weather service, it takes one to two days for water from Suicide Basin to affect levels in Mendenhall Lake.
A pressure sensor in the basin shows when it starts draining, but can’t predict the volume of water that may be released, or whether it will come as an outburst or slow release.
The U.S. Forest Service is warning kayakers, rafters and hikers to be smart on and around the lake, due to potential flooding.
Mendenhall Glacier Visitors Center naturalist Laurie Lamm says the glacier poses a danger at any time.
The face of the glacier is never a safe spot to be, because the glacier calves without warning. And if you’re close to the face of the glacier there are a couple different potential dangers. There’s the actual piece of ice falling on you, the ice popping up from underneath, or the wave that’s created by the ice. It’s not a safe spot to be,” Lamm says.
Commercial operators must file an annual operating and safety plan with the Forest Service that includes the distance their boats will stay from the glacier.
“There isn’t a Forest Service standard in our management plan that says you shall stay back X-amount of feet, so it’s recommendations,” says Natural Resource Specialist Jessica Schalkowski.
Four commercial companies are operating on the lake this year. Depending on the tour, Schalkowski says, the plans range from 300 feet to 600 feet from the face of the glacier, and 150 feet from ice bergs.
Alaska Travel Adventures offers a Mendenhall Lake trip from Skater’s Cabin beach to Nugget Falls. Adventures Tours Manager Niles Hansen says the operating plan recommends the 15-passenger canoes stay 300 feet from the face of the glacier, but they remain about a thousand feet back.
“We’re allowed to go closer, but with our canoes we just don’t feel like it’s safe,” Hansen says.
Schalkowski says it’s the inexperienced, unguided boaters that cause concern.
“Be it somebody that has a kayak personally or has rented a kayak,” she says. “They’re not with a guide that can kind of direct them to stay back from some of those dangers or recognize some of those hazards.”
The general rule of thumb: The farther away you are from the face of the glacier or ice bergs, the safer you are.