Record-breaking river flooding has destroyed at least two structures in Juneau, Alaska, and prompted local evacuations after a sudden outburst from a glacier-dammed lake inundated the region, officials say.

City officials declared a local emergency on Sunday as the flooding made the banks of the Mendenhall River unstable and blocked some roads with silt and debris.

"Although river levels continue to fall, at least two structures have been lost to the river and others are at risk and/or have been evacuated," the City and Borough of Juneau said in a news release Sunday morning.

The torrent originated from the Suicide Basin -- an ice- and water-filled basin adjacent to Juneau's Mendenhall Glacier -- and flowed into the Mendenhall Lake and river, causing the lake to crest Saturday night, according to the National Weather Service in Juneau.

The lake crested at a record 14.97 feet -- far higher than the previous record of 11.99 feet set in 2016, the weather service said. By Sunday night, the lake had lowered to around 7 feet and is expected to drop below 6 feet by Tuesday night, weather service data shows.

Though the Suicide Basin has been releasing outbursts of glacial water into the adjacent lake and river since 2011, the weather service warned that the current flooding is affecting areas that have not previously seen this flooding.

Due to unstable river banks, city officials strongly advised residents against going near the river. They also warned that some fuel tanks and hazardous material containers were impacted by the flooding.

Utilities had been restored in a majority of locations as of mid-day Sunday, the city said in its release. Crews were still working to clear blocked roadways Sunday afternoon, it said.

As the lake's levels continued to recede Sunday, the weather service announced its flood warning had expired.

"Flooding is no longer expected to pose a threat, but hazards persist in and near the Mendenhall River," the weather service said.

"Heed remaining road closures, stay out of the river and away from unstable banks, and give plenty of space for resources to provide assistance," it added.