Live · rebuilt hourly · Nov 09, 2026 16:02 UTC
Where the Rivers Go
Every perennial river in the United States, coloured by the sea it finally reaches. Right now 11,377 m³/s is leaving the country's outlet gauges every second — 3% of it bound for the Gulf of Mexico.
1.42 M NHDPlus reaches rendered from Snoflo's vector tiles, each assigned a terminal sea by point-in-polygon against USGS WBD HUC-2/HUC-4 boundaries. Outflow is the sum of the most-downstream USGS gauge on each non-tributary mainstem; percent-of-normal is relative to the day-of-year median for each gauge.
Leaving the US now
11,377 m³/s
sum of 23 outlet gauges
To the Gulf of Mexico
3%
mostly via the Mississippi
Biggest river right now
Columbia
342000 cfs · 108.0% of normal
Gauges feeding this page
7,470
USGS, updated hourly
Water year
Day 40
since 2026-10-01
Zoom in to see creeks and tributaries. Tap a river for its live level.
Gulf of Mexico3%
Pacific Ocean89%
Atlantic Ocean8%
Hudson Bay / Arctic0%
Inland basins0%
Water year so far
Cumulative volume to each sea since Oct 1, km³ · 40 of 40 days estimated
Outflow, stacked
3D columns: height = current discharge per outlet river
Biggest movers
Large gauges (>1,000 cfs) furthest from their day-of-year normal
| Gauge | Sea | cfs | % normal |
|---|---|---|---|
| PINTO CR BLW HAUNTED CANYON NR MIAMI AZ | 1240 | 688889.0% | |
| SALT RIVER AT PRIEST DRIVE NEAR PHOENIX AZ | 2020 | 237647.0% | |
| LITTLE COLORADO RIVER NEAR CAMERON AZ | 10100 | 48095.0% | |
| INDIAN CREEK NEAR MADISON AL AL | 1770 | 24313.0% | |
| Honolii Stream nr Papaikou HI | 2520 | 16579.0% | |
| WEST CLEAR CREEK NEAR CAMP VERDE AZ | 2700 | 15882.0% | |
| MCELMO CREEK ABOVE TRAIL CANYON NEAR CORTEZ CO | 2860 | 13000.0% | |
| LOS PINOS RIVER NEAR IGNACIO CO | 1760 | 12482.0% | |
| CIBECUE CREEK NEAR CHYSOTILE AZ | 1340 | 12182.0% | |
| VERDE R BLW TANGLE CREEK AZ | 20300 | 10050.0% |
Rivers ranked by what they are carrying now
Most-downstream gauge Snoflo holds for each river · tributaries indented · tap a river for its live level page
| # | River | Flows to | m³/s | cfs | % normal | |
|---|---|---|---|---|---|---|
| 1 | Columbia OR | pac | 9684 | 342000 | 108.0% | River levels → |
| 2 | → Missouri MO | gulf | 2665 | 94100 | 172.0% | River levels → |
| 3 | → Willamette OR | pac | 603 | 21300 | 97.0% | River levels → |
| 4 | → Snake WA | pac | 385 | 13600 | 91.0% | River levels → |
| 5 | Apalachicola FL | gulf | 283 | 10000 | 95.0% | River levels → |
| 6 | Hudson NY | atl | 279 | 9860 | 71.0% | River levels → |
| 7 | → Platte NE | gulf | 229 | 8100 | 139.0% | River levels → |
| 8 | Susquehanna MD | atl | 211 | 7440 | 108.0% | River levels → |
| 9 | Colorado (Lees Ferry) AZ | pac | 173 | 6120 | 67.0% | River levels → |
| 10 | Sacramento CA | pac | 151 | 5340 | 43.0% | River levels → |
| 11 | Savannah GA | atl | 136 | 4810 | 89.0% | River levels → |
| 12 | Connecticut CT | atl | 129 | 4570 | 48.0% | River levels → |
| 13 | → Green UT | pac | 119 | 4200 | 157.0% | River levels → |
| 14 | Delaware NJ | atl | 112 | 3970 | 66.0% | River levels → |
| 15 | Klamath CA | pac | 74 | 2600 | 86.0% | River levels → |
| 16 | → San Joaquin CA | pac | 61 | 2150 | 103.0% | River levels → |
| 17 | Potomac MD | atl | 52 | 1850 | 52.0% | River levels → |
| 18 | Trinity TX | gulf | 43 | 1510 | 91.0% | River levels → |
| 19 | Bear UT | inl | 19 | 669 | 93.0% | River levels → |
| 20 | Brazos TX | gulf | 17 | 583 | 26.0% | River levels → |
| 21 | Souris ND | arc | 12 | 426 | 611.0% | River levels → |
| 22 | Rio Grande TX | gulf | 1 | 22 | 10.0% | River levels → |
| 23 | Humboldt NV | inl | 0 | 0 | River levels → |
Basin by basin
Snowpack (SNOTEL, % of normal SWE) is next season's river; streamflow is this one's
Pacific Northwest
HUC 17
Streamflow69.0% of normal
Snowpack-83.0% of normal
640 gauges · 433 snow sites
California
HUC 18
Streamflow92.0% of normal
Snowpack-13.0% of normal
373 gauges · 66 snow sites
Colorado Basin
HUC 14, 15
Streamflow136.0% of normal
Snowpack-56.0% of normal
442 gauges · 254 snow sites
Great Basin
HUC 16
Streamflow98.0% of normal
Snowpack-75.0% of normal
175 gauges · 221 snow sites
Missouri Headwaters
HUC 10
Streamflow92.0% of normal
Snowpack-100.0% of normal
686 gauges · 317 snow sites
Upper Mississippi
HUC 07
Streamflow118.0% of normal
Snowpack-100.0% of normal
442 gauges · 32 snow sites
Ohio & Tennessee
HUC 05, 06
Streamflow73.0% of normal
Snowpack-100.0% of normal
665 gauges · 21 snow sites
Texas & Gulf Coast
HUC 11, 12, 13, 08
Streamflow80.0% of normal
Snowpack-50.0% of normal
1112 gauges · 81 snow sites
Southeast Atlantic
HUC 03
Streamflow84.0% of normal
Snowpackno SNOTEL
950 gauges · 0 snow sites
Northeast
HUC 01, 02
Streamflow77.0% of normal
Snowpack-91.0% of normal
917 gauges · 50 snow sites
Great Lakes
HUC 04
Streamflow76.0% of normal
Snowpack-35.0% of normal
376 gauges · 79 snow sites
Hudson Bay & Alaska
HUC 09, 19
Streamflow120.0% of normal
Snowpack-3.0% of normal
89 gauges · 177 snow sites
Follow the water home
Every reach on this map links to a live Snoflo page: river levels, state flow reports and snowpack.
Methods & data
- River network: NHDPlus V2 perennial flowlines (1.42 M reaches) baked to vector tiles with tippecanoe; zoom 3–12. Stream order drives which reaches appear at each zoom (
mzattribute). - Destination sea: USGS Watershed Boundary Dataset HUC-2 regions, split at HUC-4 in the South Atlantic–Gulf (03), California (18) and Alaska (19) regions so the Florida peninsula, Great Basin outliers and Arctic-slope Alaska are assigned correctly. Each reach is tested in the browser with Mapbox's
withinexpression against simplified polygons (tolerance 0.04°). - Outflow: sum of the most-downstream USGS gauge Snoflo holds on each mainstem (tributaries excluded to avoid double counting). The Mississippi gauge at Belle Chasse sits below the Old River Control Structure, so the Atchafalaya share is not included; true delivery to the Gulf is ~30% higher.
- Percent of normal: current discharge vs. the day-of-year median for that gauge's period of record, as computed by Snoflo's streamflow pipeline.
- Water-year volume: daily snapshots of outflow by sea integrated since Oct 1; days before snapshots began are flagged and estimated at today's rate.
- Particles: seeded on rendered reaches each frame; where National Water Model velocities are loaded they scale particle speed, otherwise speed follows stream order.
- API: /api/rivers/state (JSON, CORS, 10-min cache).
Sources: USGS NWIS, NRCS SNOTEL, NOAA National Water Model, USGS NHDPlus & WBD, Mapbox. Flows are provisional and subject to revision.