Live flood monitor

Real-time river flooding
across America.

Live USGS streamgauge readings, FEMA flood zones, NWS flood watches and warnings, and historical context — one map, refreshed throughout the day. Built for flood researchers, emergency managers, and outdoor recreationists.

Last updated July 29, 2026 · 108 sensors live
Rivers above flood
29
Watersheds elevated
62
Active flood sensors
108
USGS gauges tracked
10K+
Layers
Flow vs. normal
< 50%
~ 100%
200%
500%+
Tiles © Mapbox · Data USGS, NOAA NWS, FEMA, NRCS · Click any feature for details · Multiple layers under your click aggregate into one popup.
Right now

Rivers currently flooding or rising

Live USGS streamgauge readings aggregated by river. Percent-of-normal compares current flow to the seasonal average.

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River Observed (cfs) Seasonal avg (cfs) vs. Normal
Neosho River 246 21 ↑ 1171% of normal
Black Warrior River 5,340 4,500 119% of normal
Hawlings River 159 11 ↑ 1500% of normal
Nueces River 17,600 10 ↑ 177598% of normal
Cahaba River 1,652 199 ↑ 830% of normal
Pequest River 531 78 ↑ 682% of normal
Delaware River 14,590 1,579 ↑ 924% of normal
Black River 3,250 492 ↑ 661% of normal
Little Pigeon River 1,990 326 ↑ 610% of normal
Pecos River 4,670 179 ↑ 2603% of normal
Wild Rice River 20 93 21% of normal
Cedar River 233 123 ↑ 189% of normal
Colorado River 5,070 533 ↑ 951% of normal
Tuolumne River 1,030 115 ↑ 896% of normal
Little Delaware River 2,060 26 ↑ 7954% of normal
Tombigbee River 31,260 12,830 ↑ 244% of normal
Neversink River 4,840 76 ↑ 6352% of normal
Hackensack River 244 13 ↑ 1877% of normal
Guadalupe River 344 27 ↑ 1274% of normal
Little Colorado River 255 6 ↑ 4120% of normal
Green River 263 304 87% of normal
Lampasas River 168 9 ↑ 1900% of normal
Samish River 27 32 85% of normal
Whippany River 311 9 ↑ 3456% of normal
Saddle River 1,170 12 ↑ 9669% of normal
Tellico River 1,210 149 ↑ 812% of normal
Lamington (Black) River 175 24 ↑ 729% of normal
Musconetcong River 1,820 130 ↑ 1400% of normal
Tradewater River 803 34 ↑ 2341% of normal

29 rivers are running elevated right now. Create a free account to see the full list, follow your rivers, and get alerts.

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By basin

Watersheds running elevated

Aggregated by HUC8 watershed code. Useful for catchment-level flood-risk assessment.

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HUC8 code Watershed Observed (cfs) vs. Normal
h03160106 Middle Tombigbee-Lubbub 6,460 ↑ 241%
h05060001 Upper Scioto 288 ↑ 1021%
h13060003 Upper Pecos 2,610 ↑ 1760%
h17110002 Strait Of Georgia 27 85%
h13060001 Pecos Headwaters 1,620 ↑ 2025000%
h02030105 Raritan 700 ↑ 1212%
h05100203 South Fork Kentucky 428 ↑ 1241%
h02020006 Middle Hudson 4,223 ↑ 2194%
h03160109 Mulberry 938 ↑ 1021%
h15020016 Lower Little Colorado 255 ↑ 4120%
h12040104 Buffalo-San Jacinto 204 ↑ 2914%
h11140302 Lower Sulphur 1,270 ↑ 3273%
h12110105 Middle Nueces 17,600 ↑ 177598%
h05010006 Middle Allegheny-Redbank 2,069 ↑ 1477%
h05010001 Upper Allegheny 585 ↑ 1324%
h03150106 Middle Coosa 327 ↑ 1777%
h18040002 Middle San Joaquin-Lower 1,030 ↑ 896%
h02040203 Schuylkill 265 ↑ 730%
h05140205 Tradewater 803 ↑ 2341%
h02040104 Middle Delaware-Mongaup-Brodhead 14,614 ↑ 10489%
h02040105 Middle Delaware-Musconetcong 3,861 ↑ 1327%
h02040102 East Branch Delaware 17,830 ↑ 6653%
h02040101 Upper Delaware 15,253 ↑ 1058%
h02050201 Upper West Branch Susquehanna 21,150 ↑ 2586%
h02050202 Sinnemahoning 1,364 ↑ 1002%
h02050203 Middle West Branch Susquehanna 816 ↑ 740%
h03080103 Lower St. Johns 185,492 ↑ 136%
h07120004 Des Plaines 1,618 ↑ 539%
h08080102 Bayou Teche 686 ↑ 787%
h17110013 Duwamish 263 87%
h03160201 Middle Tombigbee-Chickasaw 24,800 ↑ 244%
h10270103 Delaware 1,790 ↑ 950%
h12030108 Richland 466 ↑ 5210%
h03160113 Lower Black Warrior 5,340 119%
h06010108 Nolichucky 270 ↑ 754%
h06010107 Lower French Broad 1,990 ↑ 610%
h03020201 Upper Neuse 248 ↑ 1240%
h03150202 Cahaba 1,652 ↑ 830%
h06010102 South Fork Holston 2,630 ↑ 1826%
h05020001 Tygart Valley 3,690 ↑ 601%
h13060011 Upper Pecos-Black 440 ↑ 1417%
h02060006 Patuxent 159 ↑ 1500%
h12100201 Upper Guadalupe 344 ↑ 1274%
h02020007 Rondout 2,470 ↑ 4372%
h11070201 Neosho Headwaters 246 ↑ 1171%
h12090302 Lower Colorado 5,070 ↑ 951%
h17110012 Lake Washington 22 80%
h09020105 Western Wild Rice 20 21%
h11010007 Upper Black 3,250 ↑ 661%
h03180002 Middle Pearl-Strong 435 ↑ 7909%
h04130002 Upper Genesee 152 ↑ 760%
h12070205 San Gabriel 195 ↑ 3558%
h03030002 Haw 344 ↑ 1341%
h05040005 Wills 467 ↑ 6554%
h12070203 Lampasas 168 ↑ 1900%
h06010204 Lower Little Tennessee 1,210 ↑ 812%
h15050202 Upper San Pedro 3,590 ↑ 53502%
h05130202 Lower Cumberland-Sycamore 4,860 ↑ 607%
h02020005 Schoharie 40,564 ↑ 33350%
h07140204 Lower Kaskaskia 1,984 ↑ 1662%
h02030103 Hackensack-Passaic 3,353 ↑ 5126%
h05130205 Lower Cumberland 274 ↑ 667%

62 watersheds are running elevated. Create a free account to see every basin.

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Go deeper

Monitoring & response toolkit

Everything on this page links into Snoflo’s gauge-level data — drill from a national view down to the readings on a single river.

Gauge-level flow reports

Every USGS streamgauge by state — live discharge, gage height, NWS flood stages, and the complete observation history.

Browse gauges →

15-day flow forecasts

PULSE probabilistic outlooks on every gauge — median, likely range, and projected stage, refreshed daily.

How PULSE works →

Engineering data & reports

Flow-duration statistics, observed peak context, CSV exports, and printable conditions reports for any gauge and date range.

Snoflo for Engineering →

Interactive national map

Layer gauges, warnings, watersheds, rain, and recreation across the country on one map.

Open the map →
Background

What causes river flooding

Flooding is rarely a single-cause event — multiple factors usually compound. The most common drivers across the U.S.

🌧

Heavy rainfall

Persistent rain saturates soils and overwhelms drainage networks. Tropical systems and atmospheric rivers are the worst culprits.

⛄

Rapid snowmelt

Spring melt pulses can deliver months of accumulated water in days — especially when warm rain falls on existing snowpack.

🧊

Ice jams

Breakup ice can block channels, forcing water to back up and inundate upstream banks. Common on northern rivers in early spring.

🌊

Storm surge

Coastal hurricanes push seawater inland. Surge combined with rainfall is the deadliest flood scenario in U.S. history.

🛡

Reservoir releases

Controlled dam releases can dramatically increase downstream flow. USACE and USBR publish release schedules, but conditions change fast.

🌌

Burn scars

Wildfire-stripped slopes can't absorb rainfall — even modest storms produce dangerous flash floods on burned watersheds for years afterward.

Safety

Flood preparedness checklist

Floodwaters rise faster than most people expect. The basics that save lives.

1
Never drive through floodwaterSix inches can stall a car; two feet floats most vehicles. Turn around — don't drown.
2
Monitor levels near youTrack the gauges upstream of your location. Snoflo's push alerts can ping you the moment a threshold is crossed.
3
Have an evacuation planKnow two routes out and where higher ground sits. If officials issue an evacuation order, leave — don't wait.
4
Move valuables upDocuments, electronics, and sentimentals to upper floors. Disconnect electrical at the main breaker if water enters the structure.
5
Trust official sourcesNWS warnings and local emergency management are the authoritative source. Snoflo data is informational; always cross-check.
6
After the water recedesDon't return until officials clear the area. Floodwater carries sewage, fuel, and downed power. Document damage before cleanup.
Frequently asked

Flood map & river monitoring FAQ

What does "percent of normal" mean?

The current flow at a gauge compared to its seasonal average for this date. 100% means flow is right at the historical norm. 200%+ means twice the typical flow — a strong indicator of flood conditions on small-to-medium rivers. Every gauge-level flow report shows its live percent-of-normal.

What's the difference between a flood watch and a flood warning?

Watch: conditions are favorable for flooding within the next 12–48 hours. Warning: flooding is happening or imminent. Both come from the National Weather Service. Snoflo overlays both as toggleable layers on the map above.

How often does Snoflo's data refresh?

USGS streamgauge readings update every 15 minutes; we re-pull every hour. NWS warning polygons update as the NWS issues them — usually within 5 minutes. FEMA flood zones are static (the National Flood Hazard Layer is updated quarterly).

What is the FEMA flood zone layer?

FEMA's National Flood Hazard Layer (NFHL) shows the 1%-annual-chance ("100-year") and 0.2%-annual-chance ("500-year") floodplains. These are based on long-term hydrologic modeling, not current conditions. Useful for property risk; not a real-time signal.

Can I get an alert when my local river floods?

Yes. Save any USGS gauge as a favorite in the Snoflo iOS app, set a threshold (e.g. "alert me at 20 ft stage"), and you'll get a push the moment it crosses. Free with a Snoflo account.

Is Snoflo a substitute for official warnings?

No. Snoflo is informational. For life-safety decisions always follow guidance from local emergency management, the NWS, and law enforcement.