Big Lost River Below Mackay Res Near Mackay Flow Report
As of July 21, 2026, Big Lost River Below Mackay Res Near Mackay is flowing at 452 cfs with a gage height of 2.67 ft, holding steady over the past 24 hours. Source: USGS gauge #13127000, refreshed throughout the day.
Historical Data
Big Lost River Below Mackay Res Near Mackay at a glance
How Big Lost River Below Mackay Res Near Mackay is running right now, where it sits on the map, and the key gauge stats.
Big Lost River Below Mackay Res Near Mackay is flowing at 452 cfs, with the water sitting 2.67 ft at the gage. Flow has held roughly steady over the past 24 hours.
This is USGS gauge #13127000 in Idaho. Over the past 10 days the average has been 450 cfs, peaking at 466 cfs.
For real-time updates and historical context, see the realtime view or the historical comparison. Browse other gauges in the Idaho flow report.
Engineering Data
Flow-duration statistics and observed peak-flow context computed from this gauge’s complete daily record (USGS #13127000).
Estimate flows at an ungauged site
Drainage-area ratio transfer from this gauge . Most reliable for hydrologically similar sites in the same watershed with area ratios between roughly 0.5 and 1.5.
Percentiles are flow-duration values computed from this gauge’s observed daily record as archived by Snoflo. Return periods are Weibull plotting-position estimates from observed annual maxima, provided as general reference context only. Always verify against official USGS NWIS records. Part of Snoflo for Engineering.
Streamflow Forecast
Over the next 5 days, Big Lost River Bl Mackay Res Nr Mackay Id is expected to hold near today's 452 cfs, toward roughly 434 cfs by 2026-07-25 (likely range 275-685 cfs) -- drier than normal for the date.
Powered by PULSE — Snoflo’s forecast engine, trained on this gauge’s full record of storms, snowmelt, and dry spells.
| Date | Expected (p50) | Likely range (p25–p75) | vs normal | Projected stage |
|---|
How does this compare to past years?
Year-over-year overlay, annual peak discharge, the full distribution of daily flows on record, and the gauge's rating curve.
Weather Forecast
Next 5 days, hour by hour
Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.
5-day forecast table
Every 3 hours, broken out across temperature, snow, rain, humidity, and wind.
| Time | Condition | Temp (°F) | Snow (in) | Rain (in) | Humidity (%) | Wind (mps) | Wind dir |
|---|---|---|---|---|---|---|---|
| Loading detailed forecast… | |||||||
15-day forecast
Daily temperatures, snow, and rain projected over the next two weeks.
Big Lost River Below Mackay Res Near Mackay
The river has its source in the mountains of central Idaho and flows for about 150 miles before it disappears into the desert near the Idaho-Nevada border. There are no major tributaries or dams along the river, but its flow is affected by seasonal trends, with peak flows occurring in late spring and early summer due to snowmelt. Interestingly, the Big Lost River is named for the fact that it often disappears underground and reemerges miles downstream, leading to the belief that the river was "lost."
Nearby streamflow levels
Cross-check Big Lost River Below Mackay Res Near Mackay's discharge against nearby gauges to spot whether the change here is local or regional.
| Gauge | Streamflow |
|---|---|
| Big Lost River Bl Mackay Res Nr Mackay Id | 452 cfs |
| Big Lost River At Howell Ranch Nr Chilly Id | 275 cfs |
| Nf Big Lost River At Wild Horse Nr Chilly Id | 85 cfs |
| Little Lost River Bl Wet Creek Nr Howe Id | 59 cfs |
| Little Lost River Nr Howe Id | 50 cfs |
| Big Lost River Nr Arco Id | 0 cfs |
Nearby snowpack data
Snowpack at SNOTEL stations near Big Lost River Below Mackay Res Near Mackay. Spring snowmelt is the dominant driver of streamflow in mountain basins -- a deep snowpack upstream means more runoff later in the season.
| SNOTEL station | Snowpack |
|---|---|
| Hilts Creek | 1 in |
| Hilts Creek | 1 in |
| Smiley Mountain | 0 in |
| Nohrsc Smiley Mountain | 0 in |
| Bear Canyon | 1 in |
| Nohrsc Bear Canyon | 1 in |
River levels & flood safety
- Read the level before you go
- A river that's runnable at one flow can be deadly at another. Check current discharge and gage height — like the values shown above — against the flood-stage thresholds, and remember levels can spike fast after rain or a dam release.
- Respect cold water
- Snowmelt rivers run cold even in summer. Sudden immersion triggers cold-water shock and saps strength within minutes. Wear a PFD, dress for the water temperature (not the air), and never wade or paddle alone.
- Watch for swiftwater hazards
- Strainers (downed trees), undercut rocks, and low-head dams are the deadliest features on moving water. High, fast, muddy water hides them. If in doubt, scout from shore and portage.
- Mind flash floods & releases
- Narrow canyons can flood from a storm miles upstream, and dam-controlled reaches can rise without warning. Know the forecast, the release schedule, and your exit before you launch.
Track Big Lost River Below Mackay Res Near Mackay in the Snoflo app
Save this gauge as a favorite, set push alerts when streamflow crosses a threshold (e.g. "alert me when Big Lost River Below Mackay Res Near Mackay crosses 5,000 cfs"), and Snoflo's iOS app will push the moment USGS reports the crossing.
About Big Lost River Below Mackay Res Near Mackay
Where does the streamflow data for Big Lost River Below Mackay Res Near Mackay come from?
Discharge, gage height, and water temperature come directly from the USGS streamflow gauge 13127000. Snoflo refreshes the time series throughout the day. Forecasts come from the NOAA / yr.no feed Snoflo's iOS app uses.
How often is the report updated?
USGS gauges report continuously (typically every 15 minutes). Snoflo pulls fresh values throughout the day — look for the "as of" timestamp on the streamflow hero card.
What's the difference between discharge and gage height?
Discharge (cubic feet per second, or cfs) is the volume of water flowing past the gauge each second. Gage height is how high the water sits at the gauge (feet). They're related by a rating curve specific to each gauge — higher water means more flow, but the exact ratio depends on channel shape.
How is "percent of median" calculated?
Today's discharge is compared to the historical median discharge on this calendar day across the gauge's full record. 100% = right on median; 200% = a very high year; 30% = a drought-level low.
What are flood stages, and is this river safe right now?
Flood stages are NWS-defined gage-height thresholds — Action, Minor, Moderate, Major — marking when nearby roads or floodplains start to be affected. "Safe" depends on your activity and skill: a level that's a fun paddle for an expert can be lethal for a wader. Always check the current level against the thresholds above and the safety links, and when in doubt, stay off the water.
Can I get alerts when Big Lost River Below Mackay Res Near Mackay rises?
Yes — flow alerts are managed in the Snoflo iOS app. Favorite this gauge, set a streamflow threshold (e.g. "alert me when discharge crosses 5,000 cfs"), and you'll get a push the moment USGS reports the crossing.
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