WATERSPORTS -- Diablo Lake, the boater access to Ross Lake in North Cascades National Park, will be off limits to normal public access until early June and again in late summer and fall for dam maintenance.
Diablo will be drawn down as low as 1192 feet above sea level or 10 feet below normal operating conditions to accommodate maintenance by Seattle City Light of the Ross Dam barge landing and ferry facilities.
Low lake levels will occur Tuesday, May 12, through June 15, and again Sept 15-Oct. 31.
During these times, Diablo Lake and the Colonial Creek Campground boat ramp will be inaccessible to motorboats and it will be difficult for paddlecraft to launch.
Lake levels will fluctuate during the draw down, but boaters should be aware that Seattle City Light may rapidly vary the lake level without notice. It is therefore recommended that boaters refrain from using their vessels on Diablo Lake from May 12-June 15 and again from September 15 through October 31 so as not to be stranded. While lake levels are low, National Park Service staff will clean sediment off the public boat ramp at Colonial Creek Campground. Normal lake levels will resume June 16 through September 14, and again on approximately November 1, 2015.
Seattle City Light will also complete work on the docks located on the east side of Diablo Lake near the Ross Haul Road. These facilities will be open to visitors on June 12, 2015.
The Ross Haul Road between Ross Powerhouse and the tunnel, as well as the Diablo Lake Trail Bridge, will be closed through June 20 and again Sept. 7-Nov. 4, 2015.
Ross Lake can be accessed via a gravel road from Hope, British Columbia on the north. Two graded-cement boat ramps at Hozomeen are normally usable from mid-June through September. There is no direct road access from the south, but canoes, kayaks and other portable craft can be launched on Diablo Lake at Colonial Creek Campground and boated five miles to the end of Diablo Lake. Boats and gear must be portaged around Ross Dam over a mile long gravel road with switchbacks (520 foot gain/120 foot loss).
Ross Lake Resort, which is open June-September, also provides portage service for portable boats, rents out small power boats, canoes, and kayaks, and provides water taxi service on the lake.
See a map of Ross Lake -- jpeg (393K), pdf (11MB) -- showing the many boat access campgrounds and other recreational opportunities that are available.
Ross Lake is a reservoir with changing water levels. The lake is generally at full pool from July - September. Docks are not usable at low water levels. For an elevational chart that shows when docks and ramps are usable, check out the Ross Lake Elevations for Dock Use handout (pdf 112K).