Source Lake Overlook, Snow Lake Trailhead, Seattle - Alpine Lakes Wilderness - Snoqualmie Pass - Central Cascades, Washington

Source Lake Overlook - 4.5 miles

Snow Lake Trailhead

Fall colors pop along the Snow Lake Trail

Fall colors pop along the Snow Lake Trail

Round-Trip Length: 4.5 miles
Start-End Elevation: 3,100’ – 4,071’ (4,071’ max elevation)
Elevation Change: +971’ net elevation gain (+990’ total roundtrip elevation gain)
Skill Level: Easy-Moderate
Dogs Allowed: Yes
Bikes Allowed: No
Horses Allowed: No
Related Trails:

Source Lake Overlook - 4.5 Miles Round-Trip

Source Lake Overlook is located below Chair Peak and Snow Lake divide in the Alpine Lakes Wilderness. This small but hydrologically significant lake forms the headwaters of South Fork Snoqualmie River, which meanders 20 miles below I-90 before turning north at North Bend.

Trail Map | Photo Gallery

Though no trail reaches the lake, a short spur off the Snow Lake Trail leads to an overlook with great views of Source Lake, the Tooth, Bryant Peak, Chair Peak and down Alpental Valley:

From the main parking lot for Alpental Ski Area, cross Alpental Road and head uphill 20 yards to the trailhead on the right side of the road, across from the double bathrooms in the upper lot.

The Snow Lake Trail climbs 150' up crib steps through mountain hemlock, silver fir and mountain ash in the direction of Snoqualmie Mountain to the north. Travel moderates above the steps and bends NW across a prominent avalanche path known as the Phantom Slide (.3 miles.).

It steadies up-valley through intervals of forest and open slide paths with occasional views of Denny Mountain and Chair Peak (6,238'), the tallest summit visible in the area.

Grades steepen past 1.5 miles (3,696’) across several small talus slopes before hairpinning at the Source Lake Overlook Trail split and headwall below Snow Lake divide (1.9 miles : 3,840').

The overlook trail bends west and follows contours around the head of Alpental Valley across a steep talus slope to the Overlook, located in a nest of talus below Chair Peak (2.25 miles : 4,017’).

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Interactive GPS Topo Map

Key GPS Coordinates - DATUM WGS84

  • N47 26.728 W121 25.407 — 0.0 miles: Snow Lake Trailhead - 3,100'
  • N47 26.988 W121 25.822 — 0.6 miles: Trail moderates after initial climb - 3,363
  • N47 27.189 W121 26.127 — 1.0 miles: Transition from forest to open slide paths - 3,484'
  • N47 27.417 W121 26.612 — 1.5 miles: Pass through several small talus slopes - 3,696'
  • N47 27.498 W121 26.890 — 1.9 miles: Source Lake Overlook Trail Junction - 3,841'
  • N47 27.518 W121 26.737 — 2.25 miles: Source Lake Overlook - 4,017'

Worth Noting

  • This trail is known locally as a “superhighway” of the wilderness. Its not uncommon to encounter hundreds of hikers here on a sunny summer weekend. Be patient and yield right-of-way to those climbing up. Arrive early to secure parking and avoid crowds.
  • Snow Lake is located only 1.4 miles from the Source Lake Overlook split, however travel is a appreciably harder beyond this point on switchbacks up to Snow Lake divide, down to Snow Lake, and back.

Camping and Backpacking Information

Car Camping at Denny Creek Campground

  • The campground has 33 Individual sites and 1 group site for 20 - 50 persons. There are 7 accessible sites. Amenities include water faucets, flush toilets and picnic tables.

  • All developed site regulations apply. Dogs must be on leash, campfires in developed rings only, quiet hours between 10 p.m. and 8 a.m. Fireworks are prohibited. Concessionaire sites require a fee paid upon arrival to the campground host. Stay limit is 14 days.

  • Reservations and current fees for the Denny Creek Campground can be made or found via or by calling 877.444.6777. Advance reservations recommended.
Backcountry Camping

  • Backcountry camping is permitted only at designated sites within 1/2-mile of Snow Lake. There is a privy available just before reaching the lake.

  • Fires are not permitted in the Snow Lake Basin.

  • An overnight Wilderness Permit must be filled out at the TH and carried for the duration of your trip. Max group size is 12.

  • Campfires are not permitted above 4000’.

Fishing Information

  • Fishing is allowed with a valid WA state fishing license.

  • Contact the Washington Department of Fish and Wildlife for more information.

Email: [email protected]
Sport | Commercial Licenses: 360.902.2434
Disability Licenses: 360.902.2460

Rules and Regulations

  • Parking for this trail is on private property – honor signage and road closures beyond Alpental ski area.
  • A free day use or overnight Wilderness Permit must be filled out at the TH and carried for the duration of your trip in the Alpine Lakes Wilderness.
  • Dogs must be leashed at all times in the Alpine Lakes Wilderness.

Directions to Trailhead

The Snow Lake Trailhead is located 1.4 miles from Exit 52 on I-90 at Snoqualmie Pass.

From I-90, take exit 52 (signed W. Summit) and turn left off the ramp for Alpental Road. Pass under the freeway and stay right where the road forks just beyond the signed Pacific Crest Trail access. Proceed 1.4 miles to the Alpental Ski Area parking lot on the left, beyond which the road is typically gated.

The parking lot holds 250 cars, and two bathrooms are located just north of the lot, across from the trailhead. 

Contact Information

Mt Baker - Snoqualmie National Forest | Snoqualmie Ranger District
902 SE North Bend Way, Bldg 1
North Bend, WA 98045

Reference Trail #1013.2

Trip Reports

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