Washington, 2003

Debris Flow and Flood in Washington, October 20, 2003

October 20, 2003 · NWS OTX · 2 events in 1 county or zone

A very deep plume of Pacific moisture impacted the Cascade Mountains beginning on the 19th of October. By the evening of the 20th, two to three inches of rain had fallen over the east slopes of the Cascades.

The toll

Deaths
0
Injuries
0
Property damage
$1.8 million
Crop damage
None recorded
Events
2

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 OTX wrote it up.

A very deep plume of Pacific moisture impacted the Cascade Mountains beginning on the 19th of October. By the evening of the 20th, two to three inches of rain had fallen over the east slopes of the Cascades. The heavy rains produced the worst flood on record along the Stehekin River near the town of Stehekin. While there is no official flood stage on the Stehekin River, the river rose 13 feet by early morning October 21st. Four homes were lost and 10 to 20 were damaged. The flood extensively damaged the park infrastructure of the Lake Chelan National Recreation Area. Hundreds of trees were washed down the river valley and deposited in the northern reaches of Lake Chelan. The village of Holden, in the mountains south of Lake Chelan, suffered damage as a result of mud slides and swollen feeder streams. Elsewhere on the east slopes of the Cascades, three mud slides cut Highway 20 between Varden Creek and Washington Pass. The largest slide covered the road with a 100 foot wide stretch of 6 foot deep mud and rocks.

Event by event

1 flood, 1 debris flow. Local standard time, as filed.

Flood, East Slopes Northern Cascades

When
October 20, 8:00 PM PST
Where
East Slopes Northern Cascades forecast zone
Property damage
$1.6 million
Reported by
EMERGENCY MANAGER

Debris Flow, East Slopes Northern Cascades

When
October 20, 8:00 PM PST
Where
East Slopes Northern Cascades forecast zone
Property damage
$150,000
Reported by
DEPT OF HIGHWAYS

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.
Debris Flow
A fast-moving slurry of mud, rock and debris, usually on a slope soaked by heavy rain or stripped by a fire.

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

The same day elsewhere

More

Every storm in Washington in 2003Every state in 2003This day in weather historyWarnings in Washington, October 2003

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: 5371205, 5371206.