At least two buildings collapsed and multiple others were endangered in Juneau, #Alaska, after a major glacial dam outburst on August 5 caused the #Mendenhall Lake to reach record highs. The city and borough of #Juneau issued a local declaration of emergency. Glacial outburst flooding happens when water in a side basin of the Mendenhall Glacier builds up enough pressure to push through the glacier, which generally acts as a dam. The water rushes through the #glacier and into the Mendenhall Lake, and on to the river, which floods. Research has found that #globalwarming and #climatechange heavily impact glaciers. The number, area, and volume of glacial lakes, have drastically grown around the world since 1990 as ice volume has decreased.