January 16, 2009 Tsunami: Columbia River Valley, WA, United States

Ref #4407:

According to a report by Adam Kelsey, Acting Chief Ranger at the park, homeowners in the Mill Canyon area contacted the park and reported that their docks had been destroyed by a large wave.

Responding rangers found that a section of hillside approximately 17 acres in size across from Breezy Bay had broken free. The subsequent landslide had fallen into the water, creating a wave that was about 30 feet high when it hit the shore about a thousand yards across the lake. A park press release provides some details:

The wave damaged or destroyed several private docks located at Breezy Bay, Moccasin Bay, Sunset Point and Arrowhead Point. Several vessels moored in the area were also swamped and left beached on land. The water reached one residence before receding and came just to the foundations of several others.

The full extent of the damage caused by the landslide is not yet known, but damage to property has been documented as far as a mile and a half downstream, and significant resource damage and erosion to the shoreline occurred as far as three miles downstream.

The park has issued a general safety warning due to the debris in the water, which is making navigation difficult. Boaters in the area have been advised to use extreme caution when boating from Cayuse Cove to Breezy Bay on the Spokane River. Along with ice deposits in the lake, there are now large trees, dock parts, and sediment deposits in yet unknown locations that have made safe navigation difficult. Due to uncertainty about conditions near the slide, people are also being advised to avoid approaching the site by land, since the ground will be quite unstable for some time and sinkholes and falling debris may occur.

Ref #13818:

On January 16th, a landslide on the Spokane River arm of Lake Roosevelt resulted in an inland tsunami, creating a wave about 30 feet high. The tsunami destroyed numerous docks and did some damage to houses along the waterfront.

Ref #14342:

On Friday, January 16th, a large landslide occurred adjacent to the Spokane River near Mill Canyon. Homeowners in the Mill Canyon area contacted the park and reported that their docks had been destroyed by a large wave. Responding rangers found that a section of hillside measuring approximately 17 acres in size had broken free across from Breezy Bay and that the subsequent landslide had fallen into the water, creating a wave that was about 30 feet high when it hit the southern shore about a thousand yards across the lake. The wave damaged or destroyed several private docks located at Breezy Bay, Moccasin Bay, Sunset Point and Arrowhead Point. Several vessels moored in the area were also swamped and left beached on land. The water reached one residence before receding and came just to the foundations of several others. The full extent of the damage caused by the landslide is not yet known. Damage to property was documented as far as a mile and a half downstream, and significant resource damage and erosion to the shoreline occurred as far as three miles downstream. The park has issued a general safety warning due to the debris in the water, which is making navigation difficult. Boaters in the area have been advised to use extreme caution when boating from Cayuse Cove to Breezy Bay on the Spokane River. Along with ice deposits in the lake, there are now large trees, dead heads, dock parts, and unknown sediment deposits that have made safe navigation difficult. Due to unknown conditions near the slide, visitors are also being advised to avoid going on land at the site, as the ground will be quite unstable for some time and sinkholes and falling debris may occur.