Flash Flood in Alaska, July 23, 2002

Name: Flash Flood in Alaska, July 23, 2002
Start: 2002-07-23T05:30
End: 2002-07-23T10:30
Location: Alaska

July 23, 2002 · NWS AJK · 1 event in 1 county or zone

The West Creek flood inundated the small, remote community of Dyea on this date. A 700-foot high moraine above the West Creek Glacier collapsed during the early morning hours of Tuesday, July 23rd.

The toll

Deaths: 0
Injuries: 0
Property damage: $450,000
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.

The West Creek flood inundated the small, remote community of Dyea on this date. A 700-foot high moraine above the West Creek Glacier collapsed during the early morning hours of Tuesday, July 23rd. This landslide collapsed into the glacial lake below, causing an estimated six foot rise in the lake level. Official estimates of between 536-766 million cubic yards of material slid into the lake. The displaced water volume surged downstream into the West Creek in a tsunami-like manner. The community of Dyea (10 miles north of Skagway) has about 20 year-round residents. With tourists in the area...35 people total had to be evacuated. Major flood, mud and silt damage resulted in Dyea. The flood waters receded a mere 5 hours after the initial flood wave gushed through...again indicating a tsunami-like flash flood due to the landslide. The main problem now is the silt and mud left behind. Fortunately no deaths nor major injuries occurred.

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 Jul 23, 1:45 AM AST, 3 hours 45 minutes earlier.

Area forecast discussion, Jul 23, 1:45 AM AST, 3 hours 45 minutes before

SOUTHEAST ALASKA FORECAST DISCUSSION
245 AM ADT TUE JUL 23 2002

.SYNOPSIS...
.SHORT RANGE...MID AND UPPER LEVEL RIDGE IS FORECAST TO REMAIN
NEARLY STATIONARY OVER SOUTHEAST ALASKA TODAY. THE SURFACE RIDGE
OVER THE PANHANDLE AND THE NORTHEAST GULF WILL ALSO MOVE LITTLE
THROUGH THIS AFTERNOON. THE NEXT OCCLUSION IN THE WESTERN GULF IS
EXPECTED TO MOVE TO THE CENTRAL GULF RUNNING UP AGAINST THE
SURFACE RIDGE BY 4PM THIS AFTERNOON. THE MID LEVEL MOISTURE FIELD
AHEAD OF THE FRONT SHOULD MOVE INTO THE PANHANDLE LATER THIS
AFTERNOON MAINTAINING THE THREAT OF PRECIPITATION OVER THE
CENTRAL AND NORTHERN PANHANDLE AND THE NORTHEAST GULF.
    BIORKA RADAR INDICATES ONLY ISOLATED ECHOES IN THE EASTERN
GULF BUT THE FLOW REMAIN OUT OF THE SOUTHWEST SO THE MARINE LAYER
WILL CONTINUE OVER THE FORECAST AREA.

.LONG RANGE...FRONT WILL CONTINUE THROUGH THE AREA LATE TONIGHT
AND WED. WILL RAISE POPS ACROSS THE BOARD TONIGHT AND WED...
INCLUDING PUTTING IN RAIN LIKELY FOR THE SOUTH WED. ONCE FRONT
GOES THROUGH THE AREA...SOME COOLER AIR WILL MOVE IN. AIRMASS
BEHIND THE FRONT NOT ALL THAT UNSTABLE...SO WILL MAINTAIN RAIN
TERMS FOR WED NIGHT INTO THU WHERE THEY ARE NOW...DUE TO ONSHORE
FLOW AT ALL LEVELS. WILL MAINTAIN POPS AS THE ARE FOR THE WED
NIGHT AND THU PERIODS ALSO.

THEREAFTER...MDT RIDGE SHOULD BE OVER THE GULF INTO FRI...WITH
WEAK SYSTEMS MOVING THROUGH IT. QUESTIONABLE WHETHER RIDGE
DYNAMICS WILL BE OFFSET BY LOW LEVEL ONSHORE FLOW...SO WILL KEEP
THE CHANCE PROBS FOR THE FRI PERIOD GOING. MODELS HINT AT A MORE
ORGANIZED FRONT MOVING INTO THE AREA SAT...GIVING A BETTER
THREAT FOR PRECIP THEN. WILL GO WITH RAIN LIKELY FOR ALL AREAS
SAT. WILL GO WITH SHOWERS LIKELY SUN AND CHANCE OF SHOWERS MON...
WITH THE ONSHORE FLOW WEAKENING DURING THAT PERIOD.

.AJK...WATCHES/WARNINGS/ADVISORIES
PUBLIC...NONE
MARINE...SCA...AREA 2A.
FIRE WEATHER...NONE

RHM/RWT

Event by event

1 flash flood. Local standard time, as filed.

Flash Flood, Northern Lynn Canal

When: July 23, 5:30 AM AST to 10:30 AM AST
Where: Northern Lynn Canal County, 10 mi N of Skagway
Property damage: $450,000
Reported by: EMERGENCY MANAGER

What these are

Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

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

The same day elsewhere

Every storm in Alaska in 2002 Every state in 2002 This day in weather history Warnings in Alaska, July 2002

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 2026-09-24. Each event’s entry at NCEI: 5315393.