Updated | 10:04 a.m. Tuesday
A flood watch for the Mendenhall Lake area has been canceled, according to National Weather Service general forecaster Jessica Voveris.
Original story | 7:04 a.m. Tuesday
A flood watch from the National Weather Service in Juneau still is in effect for Mendenhall Lake and Mendenhall River for a possible glacial dam release.
But it may not have started yet.
Instruments recorded something that happened Monday afternoon in Suicide Basin above Mendenhall Glacier, but the basin is not draining.
Pete Boyd of the National Weather Service says Mendenhall Lake and Mendenhall River water levels currently are not rising.
“What happened is the gauge that was setup at Suicide Basin, there was a significant drop that occurred, which typically is an indication of a glacial dam release,” Boyd said. “However when we started looking at the data a little more closely in conjunction with other agencies, there’s the possibility that this is just a huge calving event of the Mendenhall ice into the basin rather than the beginning of drainage. So the water level did drop but that’s if the ice being held under the water and becomes more buoyant would account for the drop in water level.”
Boyd said the Suicide Basin gauge has leveled off significantly.
“When comparing images from yesterday to today, we’re starting to see that the basin itself doesn’t seem to have dropped as much, but there’s significant changes going on with the look of the ice and the look of the water level and where all the crevasses and other events are happening.”
Boyd said they started to see the drop about 1 p.m. Monday.
“Teams have been up there throughout the evening yesterday and will probably go up today hopefully to get some more information,” Boyd said.
The National Weather Service hasn’t seen any increases in water levels at the lake, but the flood watch still is in effect because of the potential for rising water.
“This was some significant changes going on within the glacier so even if this isn’t the actual glacial dam release, it could be the event that triggers the next glacial dam release at any moment,” he said.
Boyd said it typically takes 12 to 16 hours for Mendenhall Lake and River levels to rise after a glacial dam release.
Editor’s note: This story has been updated to correct some typos.
