Juneau glacial outburst flooding begins; Mendenhall Lake and River set to hit near-record levels

Trees successful nan Mendenhall River betwixt Dimond Park and nan Botherhood Bridge aft grounds precocious h2o pursuing a glacial outburst flood successful August 2023. (Mikko Wilson/KTOO)

Water levels successful Mendenhall Lake and River began rising Sunday morning, indicating that Suicide Basin has started to drain and glacial outburst flooding has begun. The National Weather Service has issued a flood warning that is successful effect until Tuesday afternoon.

“The forecast is simply a worst lawsuit script forecast, wherever we’re assuming each of nan h2o successful nan basin is going to release,” said Nicole Ferrin, a meteorologist pinch nan National Weather Service. 

If nan basin does so drain completely, it will nonstop billions of gallons of h2o downstream and push flooding to a crest adjacent 15 feet, astir nan aforesaid tallness arsenic past year’s record-breaking flood, which caused extended harm to riverside homes. 

The Mendenhall Lake and River are expected to scope insignificant flood shape astir 10 a.m. connected Monday, and will proceed to emergence to mean levels astir 10 feet by Monday afternoon. At that stage, Mendenhall Campground will beryllium inundated pinch up to 3 feet of h2o covering debased areas and 1.5 feet of h2o blocking Skaters Cabin Road.

Sometime Monday evening flood waters could scope 12 feet, which is erstwhile h2o starts to backmost up betwixt Riverside Drive astatine Tournure Street and Mendenhall River School. This is erstwhile important erosion could begin, particularly on unarmoured riverbanks.

Flooding is expected to highest astatine 4 a.m. connected Tuesday.

“So hitting those maximum levels successful nan mediate of nan nighttime erstwhile astir group are sleeping,” Ferrin said. “They would want to make action plans up of time, truthful complete nan adjacent 24 hours.” 

Near highest flooding, respective feet of h2o will frighten yards and houses on Meander Way, Killewich Drive, View Drive and low-lying areas of Riverside Drive adjacent Melvin Park. 

The southbound broadside of Marion Drive, Rivercourt Way, Lakeview Court, Center Court, Parkview Court, Turn Street and Northland Street could besides spot much than a ft of h2o starting later Monday night. Some roads whitethorn beryllium covered.