Blackfoot River at Bonner
Montana · Tubing & floating
Measured at USGS 12340000 — Blackfoot River near Bonner MT · NWS forecast point BONM8
Reading taken Jul 28, 11:30 PM UTC
Right around its normal summer float level
At 969 CFS, this gauge is running 93% of normal for late July — close to the 1,040 CFS median USGS has recorded for this date across 92 years of record (1898–2026).
Data-derived guidance from USGS and NWS published values — not official advice, and not a safety assessment.
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Flood stages at Bonner
Official National Weather Service categories for gauge BONM8, issued by WFO MSO. Impact statements are the NWS's own wording for this location, reproduced verbatim.
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Major flood 17.0 ft
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Moderate flood 16.0 ft
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Minor flood 10.0 ft
- 10.0 ft Flooding to low lying areas adjacent to the river is possible.
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Action 9.5 ft
- Right now 2.57 ft
NWS forecast: 2.54 ft by Jul 29, 6:00 AM UTC.
12 months of flow at Bonner
Daily values from USGS gauge 12340000. Provisional data, subject to revision.
Highest crests on record at Bonner
| Stage | Flow | Date |
|---|---|---|
| 16.00 ft | — | Feb 9, 1996 |
| 11.65 ft | — | Jun 4, 1953 |
| 11.09 ft | 18,800 CFS | May 11, 2018 |
| 10.89 ft | 19,200 CFS | Jun 10, 1964 |
| 10.74 ft | 18,100 CFS | Jun 20, 1975 |
| 10.50 ft | 16,144 CFS | May 18, 1997 |
| 10.01 ft | 17,000 CFS | Jun 9, 2011 |
| 9.98 ft | 6,500 CFS | Jun 2, 1972 |
| 9.48 ft | 13,140 CFS | Jun 15, 1976 |
| 8.78 ft | 11,290 CFS | May 14, 1971 |
Historical crests published by the National Weather Service for this gauge.
About Blackfoot River at Bonner
This gauge measures Blackfoot River at Bonner, Montana — the reading paddlers, anglers and outfitters on this stretch check before committing to a shuttle.
Johnsrud Park; Missoula's biggest summer float.
Raw CFS means little on its own, so every reading on this page is shown against the USGS median for the same calendar day — 1,040 CFS for late July, from 92 years of record.
Because the National Weather Service also operates a forecast point here, the page carries the official flood-category ladder and the NWS's own stage-by-stage impact statements.
Blackfoot River at Bonner — common questions
What is the current flow on Blackfoot River at Bonner?
As of the last reading on this page, Blackfoot River at Bonner was running 969 CFS at a gage height of 2.57 ft, or 93% of the USGS median for this date. The number updates automatically from USGS gauge 12340000, which reports every 15 to 60 minutes.
Is that high or low for this time of year?
The USGS median flow for late July at this gauge is 1,040 CFS, calculated from 92 years of record (1898–2026). Comparing today's reading against that median is the only way a raw CFS number tells you anything — 200 CFS is a drought on one river and a flood on another.
How often does this reading update?
USGS transmits from this gauge every 15 to 60 minutes. This page bakes in the most recent reading when it is rebuilt, then refreshes live from USGS when you open it. Readings are provisional and subject to revision by USGS.
What flow is good for tubing Blackfoot River?
riverlvl does not publish a recommended tubing range — that call belongs to the outfitters and the local authorities who know this stretch. What this page gives you is the objective input: today's flow, the seasonal median for the same date, and where the reading sits in the 12-month record. Local outfitters generally publish their own cutoffs, and they close when the river is up.
Does rain upstream change this reading quickly?
Yes. This is a free-flowing gauge, so it responds directly to rain in the basin upstream. Flashy rises of several feet in a few hours are normal on rivers like this after a heavy storm, which is why the reading is worth checking the morning you go.
What does gage height mean versus CFS?
Gage height is how high the water surface is above the gauge's own zero point, in feet — a local measure, not depth and not elevation. CFS is cubic feet per second, the volume of water moving past the gauge. Flood stages are set in gage height; float and paddling conditions are usually discussed in CFS.