Alaska residents forced to evacuate due to bursting ice dam causing ominous flood warnings
Mendenhall Glacier's Outburst Flood Threatens Juneau, Alaska
Juneau, Alaska's capital city, is currently grappling with a flood crisis caused by an outburst flood from Suicide Basin, located behind the Mendenhall Glacier. This annual phenomenon, known as a glacier lake outburst flood (GLOF) or jökulhlaup, has been a recurring issue since around 2011 due to the glacier's retreat.
The mechanism involves rain and snowmelt accumulating behind the ice dam formed by the glacier, which then suddenly releases downstream into Mendenhall Lake and River, causing rapid rises in water levels that flood neighborhoods in Juneau, particularly in the Mendenhall Valley.
In 2023, the flood levels were record-breaking, with the Mendenhall River reaching a peak flood stage of 15.99 feet at the USGS stream gage. This surpassed previous records and caused serious flooding in the Mendenhall Valley, threatening life and property. More recently in 2025, levels reached an even higher peak of 16.65 feet, exceeding the 2023 record.
This year, experts predict the flooding could reach between 16.3 and 16.8 feet (4.96 to 5.12 meters). The expected water release from Suicide Basin took place yesterday morning, and the flood is expected to peak today. Authorities have asked residents in parts of the city and borough to evacuate as a precaution.
The outdated flood maps have significant implications for how communities prepare for such natural disasters. The tragic flood events throughout the United States this summer have pulled the U.S. Federal Emergency Management Agency's (FEMA) outdated flood maps back into the spotlight.
Sabrina Grubitz, public safety manager for the Central Council of the Tlingit and Haida Indian Tribes of Alaska and the commander of a unified local government task force responding to the flood, stated that they are prepared for this situation. Alaska Governor Mike Dunleavy issued a state disaster declaration on Monday.
Nicole Ferrin, a weather service meteorologist, stated that this will be a new record based on current information. The flood doesn't come as a surprise, as it has been a recurring issue since a small glacier on the other side of Mendenhall Glacier receded years ago, leaving a basin in its wake.
The Mendenhall Glacier's outburst floods have become more severe due to glacier retreat and ongoing climate effects, necessitating ongoing monitoring and emergency response by local and federal agencies. Authorities have installed over two miles of flood control barriers along the Mendenhall River to mitigate the damage.
| Aspect | Details | |-----------------------------------|----------------------------------------| | Cause of flooding | Outburst flood from Suicide Basin behind Mendenhall Glacier ice dam | | Mechanism | Rain and snowmelt accumulate, then suddenly release downstream into Mendenhall River and Lake | | Location affected | Juneau, Alaska’s capital city, especially Mendenhall Valley neighborhoods | | Record flood levels in 2023 | 15.99 feet flood stage peak | | Peak flood levels in 2025 | 16.65 feet flood stage peak | | Duration of outburst flood risk | Expected to continue for 25–60 years given glacier’s current conditions | | Impact | Evacuations, flooded roads, threat to homes and residents |
- The severe flooding in Juneau, Alaska is a result of AI-powered weather forecasting predicting another outburst flood from Mendenhall Glacier's Suicide Basin.
- The ongoing climate change and environmental science factors, such as glacier retreat, have played a significant role in exacerbating the space-time events that lead to these floods.
- The increased severity of Mendenhall Glacier's outburst floods highlights the need for advanced AI in weather forecasting and climate-change modeling to better equip communities in preparing for such natural disasters.
