click to enlarge mega-ripples image
Knik glacier terminus
Purple is elevation 795, orange and brown are 800 to 1,000 meters. Flood waters from Glacial Lake Atna had to get over the hump to scour the Matanuska Valley.
Regional view of Matanuska Valley
colored slope over hillshade highlighting flatness of the Knik valley and gneissic bedrock textures of the scrubbed clean upper Matanuska Valley
Lake Louise in the Copper River Basin.
Tok cut-off in the Cobb Lakes area with glacial lake Atna shore scarp elevations colored. Hwy 1 follows a shore scarp and has borrow pits on perched deltas. Scene looks NW
Lake Atna highstand elevation of 795 to 800 meters is colored
The lower Matanuska valley has flood depositional features while the upper valley is scrubbed clean to bedrock in most places with former glacial till mostly removed. The Knik valley is unaffected by flood scour and is full of till.
Mega-ripples from glacial outburst flooding at extreme exaggeration