COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-10-23 07:57 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-10-23 00:00 | 1287.37 | 2026-10-23 11:00 | 1287.52 |
| 2026-10-22 00:00 | 1287.27 | 2026-10-23 17:00 | 1287.53 |
| 2026-10-21 00:00 | 1287.2 | 2026-10-23 23:00 | 1287.55 |
| 2026-10-20 00:00 | 1287.04 | 2026-10-24 05:00 | 1287.56 |
| 2026-10-19 00:00 | 1286.9 | 2026-10-24 11:00 | 1287.58 |
| 2026-10-18 00:00 | 1286.82 | 2026-10-24 17:00 | 1287.6 |
| 2026-10-17 00:00 | 1286.48 | 2026-10-24 23:00 | 1287.61 |
| 2026-10-16 00:00 | 1285.99 | 2026-10-25 05:00 | 1287.63 |
| 2026-10-15 00:00 | 1285.62 | 2026-10-25 11:00 | 1287.65 |
| 2026-10-14 00:00 | 1285.31 | 2026-10-25 17:00 | 1287.66 |
| 2026-10-13 00:00 | 1285.21 | 2026-10-25 23:00 | 1287.68 |
| 2026-10-26 05:00 | 1287.69 | ||
| 2026-10-26 11:00 | 1287.71 | ||
| 2026-10-26 17:00 | 1287.73 | ||
| 2026-10-26 23:00 | 1287.74 | ||
| 2026-10-27 05:00 | 1287.76 | ||
| 2026-10-27 11:00 | 1287.77 | ||
| 2026-10-27 17:00 | 1287.79 | ||
| 2026-10-27 23:00 | 1287.81 | ||
| 2026-10-28 05:00 | 1287.82 | ||
| 2026-10-28 11:00 | 1287.84 | ||
| 2026-10-28 17:00 | 1287.85 | ||
| 2026-10-28 23:00 | 1287.87 | ||
| 2026-10-29 05:00 | 1287.89 | ||
| 2026-10-29 11:00 | 1287.9 | ||
| 2026-10-29 17:00 | 1287.92 | ||
| 2026-10-29 23:00 | 1287.93 | ||
| 2026-10-30 05:00 | 1287.95 | ||
| 2026-10-30 11:00 | 1287.97 | ||
| 2026-10-30 17:00 | 1287.98 | ||
| 2026-10-30 23:00 | 1288 | ||
| 2026-10-31 05:00 | 1287.96 | ||
| 2026-10-31 11:00 | 1287.86 | ||
| 2026-10-31 17:00 | 1287.74 | ||
| 2026-11-01 00:00 | 1287.62 | ||
| 2026-11-01 05:00 | 1287.48 | ||
| 2026-11-01 11:00 | 1287.32 | ||
| 2026-11-01 17:00 | 1287.15 | ||
| 2026-11-01 23:00 | 1286.95 | ||
| 2026-11-02 05:00 | 1286.74 | ||