Alaska, 2022

Flood in Alaska, October 27, 2022

October 27, 2022 · NWS AJK · 1 event in 1 county or zone

A late season glacier lake outburst flooding event took place along the Mendenhall Lake and River. Water from Suicide Basin which is dammed by the Mendenhall Glacier released starting October 25th with the Mendenhall Lake cresting above moderate flooding by October 27th.

Where it happened

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The toll

Deaths
0
Injuries
0
Property damage
None recorded
Crop damage
None recorded
Events
1

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS AJK wrote it up.

A late season glacier lake outburst flooding event took place along the Mendenhall Lake and River. Water from Suicide Basin which is dammed by the Mendenhall Glacier released starting October 25th with the Mendenhall Lake cresting above moderate flooding by October 27th. There was flooding to the Mendenhall Lake campground but it was closed for the season. There was also heavy rain from a strong weather front that masked the event at first and might have triggered the event. Rain amounts ranged from 2 to 3 inches.

This was the latest impactful outburst flooding event on record with most event happening in the summer months. Also the amount of water in Suicide Basin was the most on record for late October.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Juneau, AK wrote its last area forecast discussion before the first event at Oct 27, 2:07 PM AKST, 53 minutes earlier.

Area forecast discussion, Oct 27, 2:07 PM AKST, 53 minutes before
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In the hours before

Local storm report, Oct 27, 1:59 PM AKST, 1 hour 1 minute before
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Special weather statement, Oct 27, 2:08 PM AKST, 52 minutes before
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The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

1 flood. Local standard time, as filed.

Flood, Juneau Borough

When
October 27, 3:00 PM AKST to 7:00 PM AKST
Where
Juneau Borough County, 12.77 mi NW of Douglas to 13.77 mi NW of Douglas
Cause
Dam / Levee Break
Reported by
Official NWS Observations
Coordinates
58.414, -134.601

The USGS Mendenhall Lake gauge started to rise from moderate rainfall through the afternoon of October 25th. The lake continue to rise from heavy rain of 1 to 2 inches with more in the mountains. Mendenhall Lake water level rate of rise changed and it started to rise at a steeper and more constant rate. This is an indicator that a glacier lake outburst flooding event happening from Suicide Basin. Another indicator was old images from the basin which showed significant amount of water in the basin. Mendenhall Lake continue to rise for the next 2 days as water continue to drain from Suicide Basin and the lake crested in the afternoon hours of October 27th 10.33 feet above moderate flood stage of 10.0 feet. Skaters Cabin road was flooded along with areas within the USFS Mendenhall Lake campground. The camp ground was closed for the season but there were some roads flooded with possible erosion damage.

What these are

Flood
Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Alaska in 2022Every state in 2022This day in weather historyWarnings in Alaska, October 2022

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-30. Each event’s entry at NCEI: 1058965.