Campus Alert Archive
UAS

A Glacier-Fed Flood Breaks Juneau's Record for the Second Year in a Row

AKfloodingemergency notificationmedium confidence
Confirmed Threat

A glacial lake outburst flood from Suicide Basin near Mendenhall Glacier sent the Mendenhall River to a record crest of 15.99 feet early on August 6, 2024, breaking the prior year's record. The flood inundated the Mendenhall Valley, where the University of Alaska Southeast's main Juneau campus sits, with more than 300 homes impacted. A UAS glacier specialist publicly warned the events could grow larger in the future.

Alerts
3
Response
—
Killed
—
Injured
—
Institution
University of Alaska Southeast
Public Masters · AK
UA Alert
Confirmed Timeline

Alert Sequence

3 messages in sequence

Some alert texts below are approximate reconstructions from news coverage, not confirmed verbatim transcripts. Reconstructed texts are shown in italic with a dashed border. Verified verbatim texts have a solid border and are marked accordingly.

INITIAL ALERTSMS
Approximate reconstruction228 chars
UA Alert (Juneau): A glacial outburst flood from Suicide Basin is causing rapid rises on the Mendenhall River. Residents near the river should move to higher ground. Avoid riverbanks and low-lying areas in the Mendenhall Valley.

This text has been reconstructed from news coverage and may not reflect the exact original wording.

Reconstructed message. The exact UAS/UA Alert SMS wording was not recovered from an official archive; this paraphrases the National Weather Service flood-warning guidance for the Mendenhall Valley. isVerbatimConfirmed is false.
Suicide Basin is an ice-dammed side basin of the Mendenhall Glacier; its sudden drainage is the specific mechanism behind these recurring Juneau floods.
UPDATESMS
Approximate reconstruction228 chars
UA Alert (Juneau): The Mendenhall River has reached a record crest. Flooding continues in the Mendenhall Valley. Do not drive through floodwaters. Follow City and Borough of Juneau evacuation guidance for affected neighborhoods.

This text has been reconstructed from news coverage and may not reflect the exact original wording.

Reconstructed crest update. The Mendenhall River gauge crested at 15.99 feet, exceeding the prior year's 14.97-foot record, with streamflow over 33,000 cubic feet per second.
This is an update, not an all-clear, because flooding was ongoing and CBJ evacuation guidance for riverfront neighborhoods remained in effect.
ALL CLEARSMS
Approximate reconstruction194 chars
UA Alert (Juneau): The Mendenhall River has dropped below flood stage and the flood warning has ended. Use caution near the river due to debris and bank erosion. Normal campus operations resume.

This text has been reconstructed from news coverage and may not reflect the exact original wording.

Reconstructed all-clear. This message lifts the flood warning and is distinct from the prior ongoing-flood update.
The 2024 outburst released an estimated 14.6 billion gallons of water from Suicide Basin before levels receded.
Context

Background

Juneau's Mendenhall Valley experienced a record glacial outburst flood on August 6, 2024, the second consecutive record year. The Mendenhall River crested at 15.99 feet — above the 2023 record of 14.97 feet — as roughly 14.6 billion gallons drained from Suicide Basin, an ice-dammed pocket of the Mendenhall Glacier. Residents recounted narrow escapes as water overtopped banks and entered neighborhoods, with more than 300 homes affected. The University of Alaska Southeast's Juneau campus lies in the Mendenhall Valley, and a UAS environmental-science professor and glacier specialist warned that future floods could be larger still. UAS later partnered with regional agencies on flood inundation mapping for the valley.
Analysis

Key Findings

A Suicide Basin glacial outburst sent the Mendenhall River to a record 15.99-foot crest on August 6, 2024
It was the second consecutive record-breaking outburst flood in Juneau, exceeding the 2023 record of 14.97 feet
More than 300 homes in the Mendenhall Valley, where the UAS Juneau campus sits, were impacted
UAS glaciology faculty study Suicide Basin and warned future floods could grow larger
Outcome
No deaths were reported on campus. The Mendenhall Valley flooding damaged hundreds of homes and prompted localized evacuations near the river; UAS, whose glaciology faculty study the basin, joined regional flood-monitoring efforts.
Provenance

Sources

  1. Official
    2024 Glacial outburst flood near Juneau sets record for second year in a row - NOAA Climate.gov
    climate.gov
  2. News
    Mendenhall River neighbors recount narrow escapes after record-breaking glacial outburst flood - KTOO
    ktoo.org
  3. News
    Glacier lake outburst at Alaska's Mendenhall Glacier causes record-breaking flooding - ABC News
    abcnews.go.com
Tags
floodalaskajuneauglacial-outburstnatural-disasterclimateemergency-notification
Added May 2026Updated May 2026Via ingestion