Mowich River's headwaters from Spray Park, much of which is drained by other tributaries of the North Mowich River. Spray Creek rises in Spray Park, tumbles over Spray Falls, and collects a tributary called Grant Creek. Spray Creek then flows down from Spray Park and along the bottom of the steep slope called Eagle Cliff, after which it joins the river. Shortly below the Spray Creek confluence, the North Mowich River is joined by Crater Creek, which flows from Mowich Lake a few miles to the north. Various tributary creeks, many of which drain Spray Park, flow into Crater Creek. The North and South Mowich Rivers then join just downstream. Mowich River Proper After the North Mowich and South Mowich join to form the Mowich River Proper which flows west. It passes Paul Peak to the north, then exits Mount Rainier National Park. Just outside the park the river is joined by Meadow Creek. Then the Mowich River flows by Martin Peak to the north before curving southwest and flowing through a broad, glacier-carved valley. Rushingwater Creek joins the Mowich River just before the Mowich River itself joins the Puyallup River. Tributaries South Mowich River No major tributaries North Mowich River Spray Creek Crater Creek Mowich River Proper Meadow Creek Rushingwater Creek Geology Formed by glacial meltwater, the Mowich River contains a heavy load of sediment such as silt and gravel. After descending from the upper slopes of Mount Rainier the Mowich River flows through a broad glacier-carved valley where thick sediment deposits in the stream bed create sand and gravel bars causing the river to become complexly braided and meandering. As with other rivers sourced high on Mount Rainier, the Mowich River valley, as well as the Puyallup into which the Mowich flows, are at risk of lahars. See also List of Washington rivers List of Chinook Jargon placenames References Rivers of Washington (state) Rivers of Pierce County, Washington Chinook Jargon place names Tributaries of the Puyallup River Mount Rainier