Distance
12.0 miles roundtrip
Trail Guide
Worm Flows Route (Winter)
12.0 mi roundtrip · 5,565 ft gain · Hard · Mount St. Helens
Trail Stats
Elevation Gain
5,565 ft
Highest Point
8,365 ft
Trailhead Elevation
2,800 ft
Difficulty
Hard
Trail Type
Out And Back
Features
Winter climbing
Snowfields
Crater views
Technical Notes
Winter route from Marble Mountain Sno-Park. Snow travel required — bring snowshoes, ice axe, crampons. Route follows open slopes above treeline with avalanche exposure. Check NWAC forecast. No permit required November-March.
Getting There
Trailhead
Marble Mountain Sno-Park
FR-83, Cougar, WA
Parking: ~30 spaces
From Seattle
175 mi · 200 min drive
I-5 South to Exit 21. SR-503 East to Cougar. FR-83 to Marble Mountain Sno-Park. Sno-Park permit required in winter.
Planning Details
Best Season
November through March
Dogs Allowed
No
Required Pass
Mount St. Helens Climbing Permit
Annual: $N/A · Day: $15.00
Mountain
Mount St. Helens · 8,365 ft · South Cascades
Avalanche Forecast
Check current avalanche conditions for the Mount St. Helens zone before your trip.
Ready to plan?
Get a full trip report with weather, gear, logistics, and an event draft.