Diablo Lake
About
What It Is
Diablo Lake is a reservoir in the North Cascade mountains of northern Washington state, situated between Ross Lake and Gorge Lake on the Skagit River at an elevation of 1,201 feet (366 m) above sea level. [3] It was formed by Diablo Dam, which was constructed in 1930 and became operational in 1936, as part of the Skagit River Hydroelectric Project owned and operated by Seattle City Light. [3] The lake falls within the Ross Lake National Recreation Area inside North Cascades National Park, approximately 125 miles from Seattle. [2] [3]
Activities & Experiences
Visitors can hike two primary trails with views of the lake. The Diablo Lake Trail begins at the North Cascades Environmental Learning Center, runs approximately 7.5 to 7.6 miles out and back, gains around 1,300 feet in elevation, and provides lakeside access as well as an overlook of Ross Dam. [2] [3] The Thunder Knob Trail is a shorter option at about 3.5 miles out and back, rated moderate and considered family-friendly, passing through forest and over a stream to a south-side overlook of the lake and surrounding peaks. [2] Camping is available through drive-in, boat-in, and backpacking sites, and the Colonial Creek Campground offers a boat launch with access to the lake for kayakers and canoeers. [2] The area also offers ferry boat rides, guided tours, and educational programs. [2] A scenic overlook at State Route 20, Mile 131.7, provides views of the lake, surrounding mountains, and the historic Diablo Dam without any hiking required. [1]
Practical Access
The lake is accessible via North Cascades Highway 20, with the scenic overlook located at Mile 131.7. [1] Parking for both automobiles and buses or RVs is available at the overlook, along with picnic tables, vault or composting toilets, and trash receptacles. [1] North Cascades National Park does not charge an entrance fee. [2] Visitors planning summer trips without campground reservations are advised to arrive by mid-morning, as first-come, first-served sites fill quickly. [2] The North Cascades Visitor Center is a recommended resource for trip planning. [2]
Restrictions
Wildlife feeding is prohibited, and food and waste must not be left unattended at the overlook. [1] Two-pole fishing is prohibited at Diablo Lake. [3]
What Makes It Distinctive
Diablo Lake is recognized for its vivid turquoise water color, produced by glacial flour — fine rock particles ground by surrounding glaciers — that remains suspended in the water and refracts sunlight. [1] [2] [3] The color is most intense on sunny days in July, August, and September during peak seasonal glacial melt. [1] The lake is also unusual in that it is a functioning hydroelectric reservoir, supplying electricity to Seattle through the Skagit River dam system, making it a working piece of regional infrastructure as well as a recreational destination. [2] [3]
Sources
- Diablo Lake Overlook (U.S. National Park Service)
- Diablo Lake, WA | Turquoise Water, Hikes and Camping Guide
- Diablo Lake
- Best months: May–October
Access & fees
- no entrance fee
Things to do
- camping — multiple types
- fishing — trout species
- hiking — diablo lake trail
- hiking — thunder knob trail
- kayaking and canoeing
Amenities
- boat launch at campground
- overlook parking and facilities
Best time to visit
- peak turquoise color
Features
- diablo dam, 1930
- glacial flour coloration
Nearby
- north cascades visitor center
- ross lake and gorge lake
Good to know
- 125 miles from seattle
- arrive by mid-morning
- reservations book quickly