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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 August 19, 2026 · 141 sensors live
Rivers above flood
40
Watersheds elevated
87
Active flood sensors
141
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
Sangamon River 18,040 35 ↑ 51951% of normal
Neosho River 9,270 1,500 ↑ 618% of normal
Black Warrior River 2,140 3,160 68% of normal
Kanawha River 44,200 5,570 ↑ 794% of normal
Shade River 524 13 ↑ 4159% of normal
Edwards River 3,990 54 ↑ 7348% of normal
Salt River 153 17 ↑ 897% of normal
Tygart Valley River 15,900 684 ↑ 2325% of normal
Delaware River 1,790 189 ↑ 950% of normal
Olentangy River 517 83 ↑ 621% of normal
Kaskaskia River 1,040 23 ↑ 4444% of normal
Embarras River 349 5 ↑ 6463% of normal
White River 42,000 2,253 ↑ 1864% of normal
Deep River 395 33 ↑ 1197% of normal
Blackwater River 366 47 ↑ 779% of normal
Guyandotte River 871 135 ↑ 645% of normal
Wabash River 224,840 15,431 ↑ 1457% of normal
Mackinaw River 8,000 99 ↑ 8081% of normal
Cedar River 156 122 128% of normal
Clinch River 6,530 746 ↑ 875% of normal
Tombigbee River 6,391 11,058 58% of normal
Ohio River 77,800 12,300 ↑ 633% of normal
Little Auglaize River 576 83 ↑ 696% of normal
Tallapoosa River 3,450 536 ↑ 644% of normal
Blanchard River 2,124 139 ↑ 1530% of normal
Iowa River 3,860 552 ↑ 700% of normal
Buckhannon River 2,740 148 ↑ 1851% of normal
Samish River 19 29 66% of normal
Ottawa River 186 7 ↑ 2580% of normal
Gauley River 3,800 468 ↑ 812% of normal
Spoon River 11,300 172 ↑ 6570% of normal
Stillwater River 2,690 50 ↑ 5369% of normal
Scioto River 43,680 2,069 ↑ 2112% of normal
Williams River 809 111 ↑ 729% of normal
Cranberry River 554 83 ↑ 672% of normal
Kentucky River 13,100 2,130 ↑ 615% of normal
Maumee River 12,610 1,050 ↑ 1201% of normal
Green River 328 310 106% of normal
Casselman River 707 117 ↑ 604% of normal
Middle Fork River 1,210 77 ↑ 1579% of normal

40 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
h05100205 Lower Kentucky 13,551 ↑ 629%
h12040104 Buffalo-San Jacinto 204 ↑ 2914%
h05120112 Embarras 349 ↑ 6463%
h05030106 Upper Ohio-Wheeling 694 ↑ 816%
h05030101 Upper Ohio 1,593 ↑ 739%
h07080107 Skunk 378 ↑ 4043%
h07080105 South Skunk 265 ↑ 1325%
h07080104 Flint-Henderson 7,547 ↑ 5187%
h07100009 Lower Des Moines 13,500 ↑ 882%
h05050009 Coal 1,938 ↑ 1077%
h05050008 Lower Kanawha 44,200 ↑ 794%
h04100011 Sandusky 279 ↑ 2405%
h05050005 Gauley 5,163 ↑ 781%
h05050007 Elk 1,880 ↑ 1297%
h11070209 Lower Neosho 9,270 ↑ 618%
h18010204 Lost 311 ↑ 1026%
h05030201 Little Muskingum-Middle Island 78,138 ↑ 634%
h17110002 Strait Of Georgia 19 66%
h04100007 Auglaize 762 ↑ 848%
h04100004 St. Marys 1,540 ↑ 5500%
h04100005 Upper Maumee 3,340 ↑ 870%
h05010008 Kiskiminetas 738 ↑ 620%
h05010006 Middle Allegheny-Redbank 512 ↑ 736%
h04100008 Blanchard 2,124 ↑ 1530%
h04100009 Lower Maumee 9,270 ↑ 1392%
h04040001 Little Calumet-Galien 395 ↑ 1197%
h11140302 Lower Sulphur 1,270 ↑ 3273%
h03160113 Lower Black Warrior 2,140 68%
h05020006 Youghiogheny 1,123 ↑ 653%
h05020004 Cheat 366 ↑ 779%
h05020002 West Fork 1,040 ↑ 1828%
h05020003 Upper Monongahela 171 ↑ 633%
h05020001 Tygart Valley 36,550 ↑ 2379%
h04120101 Chautauqua-Conneaut 164 ↑ 631%
h07080207 Upper Iowa 253 ↑ 1807%
h07120004 Des Plaines 951 ↑ 362%
h07080208 Middle Iowa 4,152 ↑ 718%
h05100102 South Fork Licking 2,730 ↑ 2438%
h03160106 Middle Tombigbee-Lubbub 1,221 68%
h02070011 Lower Potomac 199 ↑ 779%
h05120208 Lower East Fork White 18,400 ↑ 1688%
h05080001 Upper Great Miami 4,631 ↑ 4780%
h05080003 Whitewater 281 ↑ 824%
h05120203 Eel 153 ↑ 1007%
h05120202 Lower White 18,700 ↑ 1385%
h05120201 Upper White 43,420 ↑ 2426%
h05120206 Upper East Fork White 10,700 ↑ 1193%
h05120204 Driftwood 232 ↑ 1693%
h05070101 Upper Guyandotte 1,635 ↑ 940%
h17110012 Lake Washington 18 79%
h17110013 Duwamish 328 106%
h03160201 Middle Tombigbee-Chickasaw 5,170 56%
h10270103 Delaware 1,790 ↑ 950%
h02070001 South Branch Potomac 381 ↑ 802%
h03080103 Lower St. Johns 215,303 ↑ 192%
h03180002 Middle Pearl-Strong 435 ↑ 7909%
h02020005 Schoharie 177 ↑ 1587%
h12030108 Richland 2,346 ↑ 23975%
h05120111 Middle Wabash-Busseron 96,017 ↑ 1240%
h05040001 Tuscarawas 592 ↑ 1853%
h05040004 Muskingum 264 ↑ 2276%
h05040006 Licking 1,380 ↑ 6449%
h06010205 Upper Clinch 6,530 ↑ 875%
h03090202 Everglades 336 ↑ 908%
h02080105 Mattaponi 173 ↑ 1153%
h05090202 Little Miami 241 ↑ 1409%
h07120003 Chicago 273 ↑ 1105%
h05120101 Upper Wabash 3,140 ↑ 12314%
h05120107 Wildcat 2,040 ↑ 2957%
h05120108 Middle Wabash-Little Vermilion 125,900 ↑ 1636%
h05120109 Vermilion 5,663 ↑ 14446%
h05060002 Lower Scioto 22,476 ↑ 1945%
h05060003 Paint 305 ↑ 760%
h05060001 Upper Scioto 26,900 ↑ 2144%
h05130202 Lower Cumberland-Sycamore 4,860 ↑ 607%
h17040201 Idaho Falls 717 ↑ 801%
h07130004 Mackinaw 8,000 ↑ 8081%
h05030204 Hocking 241 ↑ 893%
h03150109 Middle Tallapoosa 3,450 ↑ 644%
h05030203 Little Kanawha 913 ↑ 1577%
h05030202 Upper Ohio-Shade 524 ↑ 4159%
h05140102 Salt 551 ↑ 1441%
h07130009 Salt 3,489 ↑ 10477%
h07130006 Upper Sangamon 18,040 ↑ 51951%
h07130007 South Fork Sangamon 253 ↑ 740%
h07140201 Upper Kaskaskia 1,040 ↑ 4444%
h07130005 Spoon 11,300 ↑ 6570%

87 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.