May 20, 2024

CLIMBING ROUTE:  Marble Mountain Sno-Park, Winter Route, aka "Worm Flows."   FR-83 (access road) is bare pavement to Marble Mountain Sno-park.  Trail is bare wet ground for the first 1.5 miles (2.4km), then expect varying snow and bare spots on trail in the woods with a compact ski and boot trail to Chocolate Falls.  Small snow-bridge and deep postholes are opening in the area below chocolate falls in the boulders.  Expect 1 to 2 feet (30 - 60cm) of snow from trees to seismograph station (5,800 ft, 1,767 m).  Slab avalanches and glide cracks observed as recently as May 9 from the climbing route.  Northwest Avalanche Center (NWAC) has ceased avalanche forecasting for the year as of Apr 15, but climbers must exercise caution following storms, persistent sunshine after storms, prolonged warm days and cool clear nights.  Highest risk is 3,000 - 8,000 feet (914 - 2,430m).   Most recent NWAV bulletin is here.

CORNICE WARNING:   A fatality occurred on 3/30 due to a summit cornice failure and the summit rim will remain unstable until melted.  An MSHI Volunteer maintains warning stakes and flags to mark the danger zone but these may be removed/moved by winds or climbers.  Stay back at least 30 ft (9 m) from the visible edge.  The high summit drift may prevent you from having any view over the rim to the North.    

June Lake snotel reads 36 inches (3ft, 1m) snow at elevation 3,440 ft (1,048 m), down from 75 inches (6.2 ft, 1.9 m) on May 1.    

In general, expect heavy rains, snow, meltwater, ice, periods of dense fog, mixed precipitation, sub-freezing temperatures and moderate to high winds.  Know the forecast at all elevations before your climb, have cold/wet weather layers and redundant navigational aides (map, compass and GPS) for low-visibility conditions.  Due to snow and ice accumulation at all elevations, the route may not be well defined.  Always keep the wood pole cairns (trail markers) in sight as you climb.   

More information:

PERMITTING:  Refer to the recreation and permitting site for current permit dates, prices and limitations.   

Route finding:   Recommend preloading offline maps of the "Worm Flows, Winter Route" into your device and have a paper map and compass backup.   Route finding above tree line can be very challenging on days with reduced visibility, frequent winds, precipitation, fog, whiteouts, etc.  Above tree line beginning the ascent, follow the route marked by wooden poles.  As gullies melt out, more boot trails will be exposed.  

Leave No Trace: Climbers are required to utilize blue bags to pack out all human or pet waste, including toilet paper. 

Camping: There is dispersed camping and pit toilets available at the trailhead, but no running water, and bathroom services may be limited so please bring your own toilet paper, soap, water, or hand sanitizer. Please plan accordingly. 

Photos courtesy of Andy Goodwin.

Additional Forecast & Condition Resources

See the U.S. Forest Service Mount St. Helens National Volcanic Monument website for more information.

FIRE: Incident Information System has the most up to date info on all fires (prescribed or wild) around the country, or Northwest Interagency Coordination Center. Visit Washington Smoke Information, Washington's Air Monitoring Network and AirNow for the latest in Air Quality and forecasting. 

WEATHER: point forecasts- Marble Mountain SnoPark (2,700ft) and mid-slope (6,200ft) provides forecasts at three different elevations: summit 8,328ft, mid-slope 6,500ft and just above the trailhead 3,200ft.

AVALANCHE: Visit the Northwest Weather and Avalanche Center for the most up-to-date avalanche forecast information during winter months.

SNOWPACK: Visit these SNOTEL sites for recent snow pack readings on the south side of Mount St. Helens- June Lake (3,400ft) and Swift Creek (4,400ft).

This conditions report is provided in conjunction with the US Forest Service, and is intended for personal and recreational purposes only.  Safe backcountry travel requires preparation and planning, and this information may be used for planning purposes but does not provide all the information necessary for backcountry travel. Advanced mountaineering education is strongly encouraged for winter climbing.  

The user acknowledges that it is impossible to accurately predict natural events in every instance, and the accuracy or reliability of the information provided here is not guaranteed in any way. This report describes general conditions and local variations will always occur. This report expires 24 hours after the posted time unless noted otherwise.

Have a more recent report? We would love to hear from you! Email your conditions update to, photos welcome.