COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-10-26 09:50 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-10-26 00:00 | 1288.03 | 2026-10-26 23:00 | 1288.43 |
| 2026-10-25 00:00 | 1287.76 | 2026-10-27 05:00 | 1288.48 |
| 2026-10-24 00:00 | 1287.52 | 2026-10-27 11:00 | 1288.52 |
| 2026-10-23 00:00 | 1287.37 | 2026-10-27 17:00 | 1288.56 |
| 2026-10-22 00:00 | 1287.27 | 2026-10-27 23:00 | 1288.61 |
| 2026-10-21 00:00 | 1287.2 | 2026-10-28 05:00 | 1288.65 |
| 2026-10-20 00:00 | 1287.04 | 2026-10-28 11:00 | 1288.69 |
| 2026-10-19 00:00 | 1286.9 | 2026-10-28 17:00 | 1288.72 |
| 2026-10-18 00:00 | 1286.82 | 2026-10-28 23:00 | 1288.76 |
| 2026-10-17 00:00 | 1286.48 | 2026-10-29 05:00 | 1288.79 |
| 2026-10-16 00:00 | 1285.99 | 2026-10-29 11:00 | 1288.82 |
| 2026-10-29 17:00 | 1288.85 | ||
| 2026-10-29 23:00 | 1288.87 | ||
| 2026-10-30 05:00 | 1288.84 | ||
| 2026-10-30 11:00 | 1288.74 | ||
| 2026-10-30 17:00 | 1288.62 | ||
| 2026-10-30 23:00 | 1288.48 | ||
| 2026-10-31 05:00 | 1288.33 | ||
| 2026-10-31 11:00 | 1288.16 | ||
| 2026-10-31 17:00 | 1287.97 | ||
| 2026-11-01 00:00 | 1287.77 | ||
| 2026-11-01 05:00 | 1287.55 | ||
| 2026-11-01 11:00 | 1287.32 | ||
| 2026-11-01 17:00 | 1287.09 | ||
| 2026-11-01 23:00 | 1286.86 | ||
| 2026-11-02 05:00 | 1286.63 | ||
| 2026-11-02 11:00 | 1286.4 | ||
| 2026-11-02 17:00 | 1286.17 | ||
| 2026-11-02 23:00 | 1285.95 | ||
| 2026-11-03 05:00 | 1285.72 | ||
| 2026-11-03 11:00 | 1285.49 | ||
| 2026-11-03 17:00 | 1285.26 | ||
| 2026-11-03 23:00 | 1285.03 | ||
| 2026-11-04 05:00 | 1284.8 | ||
| 2026-11-04 11:00 | 1284.56 | ||
| 2026-11-04 17:00 | 1284.33 | ||
| 2026-11-04 23:00 | 1284.09 | ||
| 2026-11-05 05:00 | 1283.86 | ||