Source Lake

Alpental Backcountry

Alpine Lakes Wilderness, Washington

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Source Lake


  • Looking down the valley to Alpental from Source Lake.- Source Lake
  • Getting the first views of the Source Lake Basin.- Source Lake
  • Cat track along the South Fork of the Snoqualmie River.- Source Lake
  • Ski tracks leading back to Alpental Ski Area.- Source Lake
  • Easy skinning around Source Lake.- Source Lake
  • Nearing the end of the cat track that leads to Source Lake. - Source Lake
  • Source Lake.- Source Lake
  • Clear waters in the South Fork of the Snoqualmie River. - Source Lake
  • Looking South to Bryant Peak from Source Lake.- Source Lake
Overview + Weather
Easy access. Steep skiing. Great views.
Difficult parking. Avalanche terrain.
Alpine Lakes Wilderness, WA
Max slope angle: 
30-45 degrees
Parking Pass: 
Sno-Park Parking Permit (required in OR + WA 11.01 thru 04.30)
Total Distance: 
3.00 mi (4.83 km)
Trailhead Elevation: 
3,200.00 ft (975.36 m)
Vertical descent: 
1,500.00 ft (457.20 m)
Current Local Weather:
Adventure Description

Adventure Description


Source Lake is popular among backcountry skiers for its challenging terrain and easy access. The skin from the Alpental parking lot takes around an hour, and with a little side-hilling skiing on the way out, you can ski straight to the car. Source Lake has everything from short glades to long chutes that are filled with cliffs.  Source Lake lies at the base of many large avalanche run-outs, so be sure to check the avalanche forecast before heading out.

The tour to Source Lake is simple and relatively non-technical. Parking in the upper lot at Alpental Ski Area will shorten your hike and allow you to ski to your vehicle. Head out on the prominent skin track that passes the large water tower on your right. Use caution around the downhill traffic as you skin along the banks of the South Fork of Snoqualmie River. The cat track ends shortly before making the final push to Source Lake. After coming to the end of cat track, work your way south to gain a small bench that leads to Source Lake.

There are many lines and skiable aspects accessed through Source Lake. South of the lake you'll find steep skiing and cliffs that attract many skiers that leave the boundary of Alpental, while the area northwest of the lake contains much more moderate lines.  For those looking to escape from weekend crowds, make the extra push to Snow Lake. Getting back to the parking lot requires staying high on the south side of the valley before meeting back up with the cat track. If done correctly, only a push or two is required to make it back to the lot.

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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Field Guide + Map

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Location + Directions

Nearby Camping + Lodging

(17 within a 30 mile radius)

Nearby Adventures

(124 within a 30 mile radius)

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