Source Lake

Alpine Lakes Wilderness, Washington

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Source Lake


  • Avalanche checkpoint near the Snow Lake Trailhead.- Source Lake
  • Entering the old-growth forest.- Source Lake
  • Large avalanche slope.- Source Lake
  • First open views of Hemlock (5,604'), Bryant (5,801'), and Chair (6,238') peaks.- Source Lake
  • Crossing under avalanche debris. - Source Lake
  • Looking east at the Snoqualmie River Valley.- Source Lake
  • Following the Snow Lake Trail.- Source Lake
  • Nearing the basin, with views of The Tooth (5,519') and Bryant Peak (5,801').- Source Lake
  • The Tooth (5,519') and Bryant Peak (5,801').- Source Lake
  • Source Lake.- Source Lake
  • Snoqualmie Mountain (6,278') from the lake basin.- Source Lake
  • Chair Peak (6,238') and the route to Snow Lake.- Source Lake
  • A snow-covered tree.- Source Lake
  • An unnamed waterfall downriver.- Source Lake
  • South Fork of the Snoqualmie River.- Source Lake
  • The end of the groomed trail at the upper Alpental parking area.- Source Lake
  • - Source Lake
Overview + Weather
Old-growth forest. Large basin with great mountain vistas.
Near busy ski area with a loud speaker system.
Alpine Lakes Wilderness, WA
Pets allowed: 
Net Elevation Gain: 
700.00 ft (213.36 m)
Parking Pass: 
Not Required
Preferable Season(s):
Total Distance: 
4.00 mi (6.44 km)
Trail type: 
Trailhead Elevation: 
3,147.00 ft (959.21 m)
Current Local Weather:
Adventure Description

Adventure Description


If you fancy checking out the popular Alpental backcountry near Snoqualmie Pass and chairlifts and downhill runs aren't quite your thing, the snowshoe and cross-country ski route to Source Lake presents an excellent alternative. The lake is miniature in size and aptly named, resting at the head of the scenic South Fork of the Snoqualmie River Valley, where the flowing waters begin their long journey down to the Puget Sound. Although the route rides gradually above the banks of the Snoqualmie River, this is not the place to be during high avalanche danger, as thundering snow slides frequently reach the valley floor.

Source Lake can be accessed from both sides of the Snoqualmie River, creating the possibility for either a loop or a there-and-back trip. The first portion of the loop route follows the Snow Lake Trail along the valley's northern slopes, yielding consistent views of the surrounding mountains. From the Snow Lake Trailhead, locate the nearby avalanche checkpoint sign and set off into the shaded forest beyond. The first mile edges above the river through hearty old-growth hemlock and fir, delivering you to an open slope where Chair, Bryant and Hemlock peaks first appear to the west. From here, the route makes a continuous traverse beneath bulky cliffs and rugged avalanche piles before heading back into partially thinned tree cover. At 2 miles in, you suddenly burst into a basin with giant walls of carved powder, the signature tracks of expert-level skiing and snowboarding. 

Behold the pristine panoramas as you drop down to curve around the west edge of Source Lake. When you're ready to depart, head back east along the river's south bank. At 0.3 miles downstream from the lake, a small waterfall can be found pouring over some rocky steps. Continue descending the valley, where ski paths eventually give way to a groomed trail. This will take you back to the ski area parking lot where you can choose to unstrap and walk the road for 0.25 miles back to your vehicle or carry on with snow travel atop the river bank. 

Note: Always check weather and avalanche conditions before traveling in the backcountry.

Backcountry Safety

Winter backcountry adventures can be dangerous outdoor activities that pose significant risks as conditions affecting safety (i.e. weather, snowpack stability, avalanche hazard) are constantly changing. Prior to engaging in these activities each individual should get the proper training to make safe decisions and be equipped to use avalanche safety resources and tools. Please visit our Backcountry Skiing and Avalanche Safety post to learn more.

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Nearby Camping + Lodging

(19 within a 30 mile radius)

Nearby Adventures

(122 within a 30 mile radius)

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