Skagit River at Marblemount, WA
North Cascades & Puget Sound · USGS gauge 12181000 · Updated Oct 24, 3:19 AM PDT · USGS data, provisional
Reading time: Oct 24, 3:00 AM PDT · Provisional data
Flow is in a typical range for the date. Rivers are generally easiest to fish and float when they are near their normal flow, but this status says nothing about water clarity, hatches, hazards such as wood in the river, or dam releases.
- Vs. normal for this date
- 21st percentile
- Typical range (25th–75th)
- 3,722–5,940 cfs
- Median for this date
- 4,610 cfs
- 7-day low / high
- 3,280 / 4,710 cfs
Plain-language explanation
Skagit River at Marblemount is flowing at 3,490 cubic feet per second (cfs) as of Oct 24, 3:00 AM PDT. That is on the low side for this time of year: lower than about 79% of the daily flows this gauge has recorded for this date (give or take 7 days) over 57 years of record (1943–2026).
The middle half of those historical flows runs from 3,722 to 5,940 cfs, with a median of 4,610 cfs; the lowest 10% of days are at or below 2,650 cfs and the highest 10% at or above 8,090 cfs.
Over the last 24 hours the flow has been falling (-14.3%). In the last 7 days it ranged from 3,280 to 4,710 cfs.
Regulated flow: upstream dams or diversions influence this gauge, so the “normal range” above reflects managed flows and can differ from natural river behavior.
Why this status: Flow is within the range this gauge normally sees at this time of year (or the deviation is too small in absolute terms to matter).
7-day trend
Hourly flow in cfs, Pacific time. The shaded band is the typical range (25th–75th percentile) for this date, shown when it falls within the chart.
| Day (Pacific) | Mean cfs | Percentile | Status that day |
|---|---|---|---|
| Sun Oct 18 | 3,404 | 25th | Fishable/Floatable |
| Mon Oct 19 | 4,057 | 41st | Fishable/Floatable |
| Tue Oct 20 | 4,208 | 45th | Fishable/Floatable |
| Wed Oct 21 | 3,992 | 37th | Fishable/Floatable |
| Thu Oct 22 | 4,122 | 39th | Fishable/Floatable |
| Fri Oct 23 | 3,745 | 26th | Fishable/Floatable |
| Sat Oct 24 (so far) | 3,512 | 22nd | Fishable/Floatable |
Seasonal context
Shaded band: 10th–90th percentile of daily flows through the year; dashed line: median. Log scale. Dot: today's flow. Based on 57 years of USGS daily data (1943–2026).
About this gauge
- USGS site
- USGS-12181000
- USGS name
- Skagit River At Marblemount, Wa
- Drainage area
- 1,381 sq mi
- Location
- 48.5337, -121.4298
- Record in this analysis
- 1943–2026
Typical uses
Notes: Gauge is downstream of the Skagit hydro dams, so flows are partly regulated. (Hand-written general note, not from USGS data.)
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