Live · rebuilt hourly · Nov 12, 2026 12:25 UTC
Where the Rivers Go
Every perennial river in the United States, coloured by the sea it finally reaches. Right now 19,662 m³/s is leaving the country's outlet gauges every second — 44% 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
19,662 m³/s
sum of 19 mainstem outlet gauges
To the Gulf of Mexico
44%
mostly via the Mississippi
Biggest river right now
Columbia
342000 cfs · 108% of normal
Gauges feeding this page
7,470
USGS, updated hourly
Water year
Day 43
since 2026-10-01
Loading 1.4 million river reaches…
Zoom in to see creeks and tributaries. Tap a river for its live level.
Gulf of Mexico44%
Pacific Ocean51%
Atlantic Ocean4%
Hudson Bay / Arctic0%
Inland basins0%
Water year so far
Cumulative volume to each sea since Oct 1, km³ · 39 of 43 days estimated
Outflow, stacked
3D columns: height = current discharge per outlet river
Biggest movers
Rivers above 5,000 cfs furthest from their day-of-year normal
| Gauge | Sea | cfs | % normal |
|---|---|---|---|
| St. Johns River Near Melbourne Fla FL | 6930 | 1400% | |
| Des Moines River At Ottumwa IA | 22600 | 1222% | |
| Iowa River Below Coralville Dam Nr Coralville IA | 7880 | 1010% | |
| E Fk Trinity Rv Nr Forney TX | 6120 | 713% | |
| Kansas R At Lecompton KS | 8030 | 630% | |
| Cedar River At Cedar Rapids IA | 11700 | 511% | |
| San Joaquin R A Jersey Point Ca CA | 24200 | 23% | |
| Minnesota River Near Jordan MN | 9500 | 367% | |
| St. Louis River At Scanlon MN | 5910 | 336% | |
| White River At Batesville AR | 38000 | 254% |
Rivers ranked by what they are carrying now
Highest-flow gauge Snoflo holds on each river (hover a name for the gauge) · tributaries indented · tap a river for its live level page
| # | River | Flows to | m³/s | cfs | % normal | |
|---|---|---|---|---|---|---|
| 1 | Columbia OR | pac | 9684 | 342000 | 108% | River levels → |
| 2 | Mississippi MS | gulf | 8127 | 287000 | 80% | River levels → |
| 3 | → Ohio KY | gulf | 2081 | 73500 | 80% | River levels → |
| 4 | → Missouri MO | gulf | 2019 | 71300 | 136% | River levels → |
| 5 | → Willamette OR | pac | 603 | 21300 | 97% | River levels → |
| 6 | → Snake WA | pac | 385 | 13600 | 91% | River levels → |
| 7 | → Arkansas OK | gulf | 331 | 11700 | 201% | River levels → |
| 8 | Mobile-Alabama AL | gulf | 252 | 8900 | 65% | River levels → |
| 9 | Hudson NY | atl | 246 | 8690 | 57% | River levels → |
| 10 | Apalachicola FL | gulf | 240 | 8480 | 87% | River levels → |
| 11 | Susquehanna MD | atl | 186 | 6580 | 99% | River levels → |
| 12 | Colorado (Lees Ferry) AZ | pac | 172 | 6060 | 66% | River levels → |
| 13 | → Platte NE | gulf | 169 | 5980 | 94% | River levels → |
| 14 | Sacramento CA | pac | 151 | 5340 | 43% | River levels → |
| 15 | Connecticut CT | atl | 144 | 5090 | 48% | River levels → |
| 16 | Savannah GA | atl | 125 | 4430 | 83% | River levels → |
| 17 | → Green UT | pac | 114 | 4040 | 150% | River levels → |
| 18 | Delaware NJ | atl | 91 | 3210 | 59% | River levels → |
| 19 | Klamath CA | pac | 74 | 2600 | 86% | River levels → |
| 20 | → San Joaquin CA | pac | 61 | 2150 | 103% | River levels → |
| 21 | Potomac MD | atl | 50 | 1770 | 44% | River levels → |
| 22 | Brazos TX | gulf | 44 | 1540 | 72% | River levels → |
| 23 | Trinity TX | gulf | 43 | 1510 | 92% | River levels → |
| 24 | Bear UT | inl | 20 | 706 | 86% | River levels → |
| 25 | Souris ND | arc | 12 | 426 | 312% | River levels → |
| 26 | Rio Grande TX | gulf | 1 | 22 | 10% | River levels → |
| 27 | 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
Streamflow71% of normal
Snowpack8% of normal
641 gauges · 449 snow sites
California
HUC 18
Streamflow92% of normal
Snowpack67% of normal
374 gauges · 66 snow sites
Colorado Basin
HUC 14, 15
Streamflow129% of normal
Snowpack33% of normal
440 gauges · 294 snow sites
Great Basin
HUC 16
Streamflow96% of normal
Snowpack25% of normal
175 gauges · 244 snow sites
Missouri Headwaters
HUC 10
Streamflow89% of normal
Snowpack13% of normal
688 gauges · 334 snow sites
Upper Mississippi
HUC 07
Streamflow113% of normal
Snowpackno SNOTEL
442 gauges · 35 snow sites
Ohio & Tennessee
HUC 05, 06
Streamflow70% of normal
Snowpackno SNOTEL
665 gauges · 23 snow sites
Texas & Gulf Coast
HUC 11, 12, 13, 08
Streamflow83% of normal
Snowpack50% of normal
1115 gauges · 88 snow sites
Southeast Atlantic
HUC 03
Streamflow71% of normal
Snowpackno SNOTEL
950 gauges · 0 snow sites
Northeast
HUC 01, 02
Streamflow63% of normal
Snowpack8% of normal
917 gauges · 50 snow sites
Great Lakes
HUC 04
Streamflow66% of normal
Snowpack65% of normal
376 gauges · 79 snow sites
Hudson Bay & Alaska
HUC 09, 19
Streamflow108% of normal
Snowpack97% of normal
89 gauges · 187 snow sites
Follow the water home
Tap any river above for its live level, or go deeper: the full interactive map, 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: for each mainstem, the most-downstream USGS gauge Snoflo holds, or else its highest-discharge gauge (flow accumulates downstream, so this is the best outlet proxy); tributaries are listed but excluded from the sums to avoid double counting. Where the lowest gauge sits well upstream of the coast (Mississippi, Yukon) the sea totals are lower bounds.
- 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.