Update: Flood warning cancelled for Mendenhall Valley

The Mendenhall River was at 9.16 feet this morning and is expected to crest near flood stage at 11.15 feet on Thursday night. The quickly rising water is a result of a glacial lake breaking and releasing a lake from approximately 2 miles up the Mendenhall Glacier.

The Mendenhall River at near flood levels in 2012. (Photo by Heather Bryant/KTOO)

Updated | Aug. 13, 2014 – 6:07 a.m.

The flood warning for both Mendenhall Lake and Mendenhall River was cancelled Wednesday morning at 5 a.m. as water levels continued dropping.

Mendenhall Lake peaked at 10.87 feet at 6:30 p.m. Tuesday evening while Mendenhall River peaked at 12.8 feet about 8 p.m.

Meteorologist Jonathan Garner of the National Weather Service office in Juneau said the flooding could have been a combination of another jökulhlaup and heavy rainfall on Monday night and Tuesday morning.

“Not exactly sure where the water came from with respect to the (Mendenhall) Glacier,” Garner said. “It might’ve been Suicide Basin. We haven’t been able to confirm that yet.”

Original Story | Aug. 12, 2014 – 3:51 p.m.

The National Weather Service has issued a flood warning for Mendenhall Lake and Mendenhall River in Juneau, following the suspected release of water from a glacially dammed lake.

Last month, a glacial outburst helped push floodwaters over side roads and into some garages and resulted in Mendenhall Lake rising to 11.82 feet, a new record.

Meteorologist Edward Liske says lake levels are expected to reach 11.6 feet by late Tuesday or Wednesday morning. Moderate flood stage is 10 feet.

The agency said water has been reported in some garages along View Drive.

Liske said officials were re-evaluating the river gauges.

He said people at the Mendenhall Glacier visitor center reported seeing ripples on the side of the glacier, indicating another outburst had occurred. The city also received recent soaking rains.