Big Lost River below Mackay Reservoir
Future / Actual / Minor
OWP 2.0 WWA Modal Title
01/11/2021, 10:04 PM UTC through 01/11/2021, 10:04 PM UTC
Sender
Sent
- Warning: no valid ratings curve available. Transformations to and from FEET/CFS/KCFS will not happen.
Traces and Thresholds Click to turn on/off display
Observed (OBS) 06/24/2025 4:45 PM MDTOfficial Forecast (FCST) 06/24/2025 3:23 PM MDTRecord: 6.1 ftCATEGORY STAGE 
Minor Flooding 4.3 ft Action 3.8 ft Reliability of the Forecast:
NOTE: Forecasts are issued routinely year-round.
National Water Model Hydrograph
Official NWS streamflow forecasts are produced by NWS hydrologic forecasters for river gauge locations using hydrologic models which are calibrated to that location. This process considers additional guidance and information, including local expertise and experience, to produce the best forecast possible. The NWM output provides supplemental guidance to NWS forecasters and should not be considered an official NWS river forecast.
Flood Impacts
- 4.3 - Lowland flooding below Mackay Dam through the Darlington Flats. US Highway 93 may be impacted at the curve by Leslie between 3900 North and 4050 North.
- 3.8 - Near bankfull from Mackay Dam through the Darlington Flats. Water is likely to start to seep in low-lying areas in the Darlington Flats.
Gauge Info
| Coordinates | 43.9391, -113.648 |
| RFC | NWRFC |
| State | ID |
| WFO | PIH |
| County | Custer |
| Data Provider(s) | |
| US Geological Survey | USGS--Water Resources of the United States |
| USGS | 13127000 |
Gauge Location
Recent Crests
| 1. | 2.78 ft | on 06-07-2020 |
| 2. | 4.19 ft | on 06-17-2019 |
| 3. | 4.95 ft | on 05-27-2018 |
| 4. | 5.09 ft | on 06-10-2017 |
| 5. | 3.91 ft | on 06-09-2016 |
Recent Crests
| 1. | 2.78 ft | on 06-07-2020 |
| 2. | 4.19 ft | on 06-17-2019 |
| 3. | 4.95 ft | on 05-27-2018 |
| 4. | 5.09 ft | on 06-10-2017 |
| 5. | 3.91 ft | on 06-09-2016 |
| 6. | 3.15 ft | on 06-10-2015 |
| 7. | 3.12 ft | on 06-06-2014 |
| 8. | 3.30 ft | on 06-11-2013 |
| 9. | 4.05 ft | on 06-05-2012 |
| 10. | 4.77 ft | on 06-30-2011 |
| 11. | 4.44 ft | on 06-28-2010 |
| 12. | 4.64 ft | on 06-21-2009 |
| 13. | 3.29 ft | on 06-24-2008 |
| 14. | 2.87 ft | on 05-15-2007 |
| 15. | 5.52 ft | on 06-09-2006 |
| 16. | 4.07 ft | on 05-30-2005 |
| 17. | 6.08 ft | on 06-06-1986 |
| 18. | 5.65 ft | on 06-30-1982 |
| 19. | 5.93 ft | on 06-17-1974 |
| 20. | 5.89 ft | on 06-14-1965 |
| 21. | 5.65 ft | on 05-26-1958 |
| 22. | 5.79 ft | on 06-10-1921 |
Historic Crests
| 1. | 6.08 ft | on 06-06-1986 |
| 2. | 5.93 ft | on 06-17-1974 |
| 3. | 5.89 ft | on 06-14-1965 |
| 4. | 5.79 ft | on 06-10-1921 |
| 5. | 5.65 ft | on 06-30-1982 |
Historic Crests
| 1. | 6.08 ft | on 06-06-1986 |
| 2. | 5.93 ft | on 06-17-1974 |
| 3. | 5.89 ft | on 06-14-1965 |
| 4. | 5.79 ft | on 06-10-1921 |
| 5. | 5.65 ft | on 06-30-1982 |
| 6. | 5.65 ft | on 05-26-1958 |
| 7. | 5.52 ft | on 06-09-2006 |
| 8. | 5.09 ft | on 06-10-2017 |
| 9. | 4.95 ft | on 05-27-2018 |
| 10. | 4.77 ft | on 06-30-2011 |
| 11. | 4.64 ft | on 06-21-2009 |
| 12. | 4.44 ft | on 06-28-2010 |
| 13. | 4.19 ft | on 06-17-2019 |
| 14. | 4.07 ft | on 05-30-2005 |
| 15. | 4.05 ft | on 06-05-2012 |
| 16. | 3.91 ft | on 06-09-2016 |
| 17. | 3.30 ft | on 06-11-2013 |
| 18. | 3.29 ft | on 06-24-2008 |
| 19. | 3.15 ft | on 06-10-2015 |
| 20. | 3.12 ft | on 06-06-2014 |
| 21. | 2.87 ft | on 05-15-2007 |
| 22. | 2.78 ft | on 06-07-2020 |
Vertical Datum Table
| type | NGVD29 |
|---|---|
| major Flooding | N/A |
| moderate Flooding | N/A |
| minor Flooding | 5950.69 ft |
| action | 5950.19 ft |
| Latest Value | 5948.93 ft |
| Gauge Zero | 5946.39 ft |
Gauge Photos
No Images Found
Probability Information
No Images Available
Collaborative Agencies
The National Weather Service prepares its forecasts and other services in collaboration with agencies like the US Geological Survey, US Bureau of Reclamation, US Army Corps of Engineers, Natural Resource Conservation Service, National Park Service, ALERT Users Group, Bureau of Indian Affairs, and many state and local emergency managers across the country. For details, please click here.