The National Weather Service office in Juneau issued a special weather statement Tuesday at 9:49 a.m. saying a second glacial outburst flood could be underway in Juneau. Now, meteorologists say it’s probably not.
Nathan Compton, a meteorologist at the Weather Service in Juneau, said there’s no reason for the public to be concerned.
“This is not a release, and furthermore, if it were a release, it wouldn’t even reach flood stage at this point,” Compton said.
He said that’s because not enough water has collected in Suicide Basin — the glacial lake dammed by Mendenhall Glacier — for it to flood the Mendenhall River.
A minor flood stage starts at 9 feet. If the basin released now, the Weather Service forecasts a crest a foot or more below that. The flood last month peaked at 14.7 feet.
Compton said meteorologists will continue watching the basin to see if it drains, and will update the weather statement when they can confirm whether or not it’s releasing. But he said the observed drop in water level looks like it could have been a glitch.
“It could be a wide variety of different things,” he said. “The laser gauge that’s up on the basin could be interacting with some ice that’s moving through.”
According to data from the U.S. Geological Survey, it’s not uncommon for the basin to release more than once in a year. Since 2023, second releases that took place in September or October were significantly smaller than initial floods in August.
