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New: Click on a gage name for graph and additional data.

USGS Gage Name

Time, Date



Flow Change

North Fork Snoqualmie River 3:15 PM, 9/29/2020 2.81 229 -2
Middle Fork Snoqualmie River 3:15 PM, 9/29/2020 2.37 546 -16
South Fork Snoqualmie River 3:15 PM, 9/29/2020 10.78 91 0
Sum of Snoqualmie River Forks 3:15 PM, 9/29/2020 n/a 866 -18
Snoqualmie River near Snoqualmie 4:10 PM, 9/29/2020 4.20 1,120 0
Snoqualmie River near Carnation 3:15 PM, 9/29/2020 46.18 1,440 0
Snoqualmie River at Duvall 3:30 PM, 9/29/2020 21.11 n/a -0.04 (stage, in feet)

* Gage data currently unavailable.

** Sum currently unavailable.


This data was requested from USGS at 9/29/2020 4:15:08 PM.

The next request for USGS data is expected in approximately 8 minutes from when this page was loaded.

The flood phases of the Snoqualmie River are based on the sum of flow for the North, Middle and South forks. The sum of the forks represents the most recent flows available from three independent gages providing the best available flood warning information. If a gage has an older sampling time than others, its most recent measurement is used in calculating the sum of the forks. Flood phases remain in effect after flows decrease below designated thresholds until the river crests at the Carnation gage.

Snoqualmie River near Carnation real-time provisional data greater than 9,000 cfs (gage heights greater than about 50 ft) are not reliable due to unsteady flow conditions during high flows. Under these conditions, a loop stage-discharge rating exists such that the true discharge is generally greater than indicated on a rising hydrograph and less than indicated on a falling hydrograph. Corrections are applied following a high-flow event but data remain provisional until approved.

c.f.s. = cubic feet per second.
King County provides funding to the United States Geological Survey (USGS) to support the operation and maintenance of river and stream gages and related systems. The term "gage" is defined as an instrument for measuring or testing. USGS uses the term "streamgage" to describe their equipment that obtains estimates of the amount of water flowing in streams and rivers. More information about USGS streamgages

Chart of recent / forecast data

Snoqualmie River Flood Phases
Phase Phase Threshold (sum of the Forks) Description Roads that may overtop and close
1 6,000 c.f.s. Internal Alert  
2 12,000 c.f.s. Lowland flooding Neal Rd, SE Reinig Rd, West Snoqualmie River Rd NE (Walker Rd) Snoqualmie Meadowbrook Rd, Mill Pond Rd.
3 20,000 c.f.s. Flooding of varied depths occurs in the entire Snoqualmie Valley Fall City -Carnation Rd, Tolt Hill Rd, NE 124th St.
4 38,000 c.f.s. Some residential areas may experience dangerous high velocities and flooding of homes. Woodinville-Duvall Rd, SR 203 between Duvall and Carnation, Moon Valley Rd, South Fork Rd
Snoqualmie River gages map - flooding
Recent High Flow Data
High Flow Event Sum of the Forks Snoqualmie River near Snoqualmie Snoqualmie River near Carnation
December 8-9, 2015 41,120 c.f.s.* 49,500 c.f.s.* 56,200 c.f.s.* 59.78 ft*
November 17-18, 2015 42,700 c.f.s.* 48,000 c.f.s.* 46,600 c.f.s.* 58.85 ft*
January 5-6, 2015 44,210 c.f.s. 50,100 c.f.s. 53,900 c.f.s. 59.24 ft
January 7-8, 2009 54,110 c.f.s. 60,700 c.f.s. 82,900 c.f.s. 62.21 ft
November 6-7, 2006 53,500 c.f.s. 55,000 c.f.s. 71,800 c.f.s. 61.28 ft
February, 1996 43,740 c.f.s. 51,700 c.f.s. 61,600 c.f.s. 60.34 ft
November, 1995 47,960 c.f.s. 50,200 c.f.s. 62,400 c.f.s. 60.30 ft
November, 1990 48,250 c.f.s. 74,300 c.f.s. 65,200 c.f.s. 60.70 ft

*provisional data

Snohomish County Flood Warning Information (external link), 425-388-5060

The National Weather Service also provides access to provisional gage data:

Snoqualmie River near the Falls (external link)

Snoqualmie River near Carnation (external link)

Other Flood-related Information

» Historical flood photos
» Return to the The Flood Warning System Page
» Return to King County Flooding Services
» See other Snoqualmie Basin Topics