The primary purpose of this report is to describe the background information, methods and results of a surficial geology inventory within the North Cascades National Park Service Complex (NOCA). A secondary goal is to provide an overview of bedrock geology, climate and hydrology as they affect landform processes. The study area for this report is the Thunder Creek Watershed, which is defined as Thunder Creek and its tributaries. Thunder Creek flows north into Diablo Lake, a hydroelectric project located within NOCA.