Gallatin River level at Big Sky
Montana · Paddling & whitewater
Measured at USGS 06043500 — Gallatin River near Gallatin Gateway, MT · NWS forecast point GLGM8
Reading taken · as of 28 min ago
On the low side — bony, but runnable in a plastic boat
At 370 CFS, this gauge is in the lowest quarter of the 97 years USGS has recorded for this date (1889–2026), at 81% of the 459 CFS median.
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Flood stages at Big Sky
National Weather Service categories for gauge GLGM8, WFO TFX. Impact wording is the NWS's own, verbatim.
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Major flood 7.5 ft · 11,200 CFS
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Moderate flood 7.0 ft · 9,726 CFS
- 7.0 ft Minor roads in gallatin gateway covered with water.
- 7.1 ft Water flows over road connecting two bridges over gallatin river. Three forest service campgrounds flood, including the one at squaw creek.
- 7.2 ft Small bridge near gallatin gateway and a few homes west of town are beginning to flood.
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Minor flood 6.0 ft · 6,886 CFS
- 6.0 ft Water flows over roads as well as several smalller bridges. Several forest service campgrounds as well as some home west of town begin to flood.
- 6.1 ft Flooding of the lowlands along the gallatin river.
- 6.3 ft Water flows over the axtell and irwin bridges.
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Action 5.0 ft · 4,846 CFS
- 5.0 ft Gallatin river on west side of gallatin gateway can come out of banks at mill road near where the road crosses the river. Water may work into area yards and fields, and may encroach onto mill road.
- Right now 1.41 ft
Flow history at Big Sky
Daily values from USGS 06043500, updated every 15 to 60 minutes; NWS forecast for GLGM8 reissued through the day. Provisional.
Highest crests on record at Big Sky
12 on record
| Stage | Flow | Date |
|---|---|---|
| 7.38 ft | 9,100 CFS | Jun 17, 1974 |
| 6.71 ft | 9,160 CFS | Jun 2, 1997 |
| 6.70 ft | 8,980 CFS | Jun 13, 2022 |
| 6.51 ft | 8,410 CFS | Jun 30, 2011 |
| 6.50 ft | 7,640 CFS | Jun 6, 1991 |
| 6.49 ft | 7,610 CFS | Jun 27, 1971 |
| 6.48 ft | 7,600 CFS | Jun 9, 1970 |
| 6.31 ft | 7,330 CFS | Jun 6, 1995 |
| 6.27 ft | 7,950 CFS | Jul 4, 1975 |
| 6.23 ft | 7,230 CFS | Jun 15, 1959 |
Crests published by the National Weather Service.
About Gallatin River at Big Sky
In Montana — the reading paddlers, anglers and outfitters here check before committing to a shuttle. Gallatin Canyon and the Mad Mile.
Gallatin River at Big Sky — common questions
3 questions
How fast can Gallatin River at Big Sky come up?
Fast. It is free-flowing, so rain upstream moves it directly. Several feet in a few hours is normal after a heavy storm.
Is Gallatin River at Big Sky high or low for this time of year?
The USGS median flow for late September here is 459 CFS, from 97 years of record (1889–2026). Today sits in the lowest quarter of those years, at 81% of the median. The comparison is what makes the raw number mean anything: the same reading is a drought on one river and a flood on another.
How often does this reading update?
USGS transmits from gauge 06043500 every 15 to 60 minutes, and the National Weather Service reissues the flood forecast for GLGM8 a few times a day — more often when the river is rising. This page refreshes from both when you open it. The timestamp is in the gauge's local time.