COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-06-26 08:36 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-06-26 00:00 | 1285.19 | 2026-06-26 17:00 | 1285.01 |
| 2026-06-25 00:00 | 1285.39 | 2026-06-26 23:00 | 1285 |
| 2026-06-24 00:00 | 1285.23 | 2026-06-27 05:00 | 1284.99 |
| 2026-06-23 00:00 | 1285.1 | 2026-06-27 11:00 | 1284.97 |
| 2026-06-22 00:00 | 1284.66 | 2026-06-27 17:00 | 1284.96 |
| 2026-06-21 00:00 | 1283.69 | 2026-06-27 23:00 | 1284.94 |
| 2026-06-20 00:00 | 1282.98 | 2026-06-28 05:00 | 1284.92 |
| 2026-06-19 00:00 | 1282.95 | 2026-06-28 11:00 | 1284.9 |
| 2026-06-18 00:00 | 1282.21 | 2026-06-28 17:00 | 1284.98 |
| 2026-06-17 00:00 | 1281.32 | 2026-06-28 23:00 | 1285.05 |
| 2026-06-16 00:00 | 1281.16 | 2026-06-29 05:00 | 1285.12 |
| 2026-06-29 11:00 | 1285.2 | ||
| 2026-06-29 17:00 | 1285.27 | ||
| 2026-06-29 23:00 | 1285.34 | ||
| 2026-06-30 05:00 | 1285.42 | ||
| 2026-06-30 11:00 | 1285.49 | ||
| 2026-06-30 17:00 | 1285.56 | ||
| 2026-06-30 23:00 | 1285.63 | ||
| 2026-07-01 05:00 | 1285.71 | ||
| 2026-07-01 11:00 | 1285.78 | ||
| 2026-07-01 17:00 | 1285.85 | ||
| 2026-07-01 23:00 | 1285.93 | ||
| 2026-07-02 05:00 | 1286 | ||
| 2026-07-02 11:00 | 1286.07 | ||
| 2026-07-02 17:00 | 1286.13 | ||
| 2026-07-02 23:00 | 1286.2 | ||
| 2026-07-03 05:00 | 1286.27 | ||
| 2026-07-03 11:00 | 1286.33 | ||
| 2026-07-03 17:00 | 1286.4 | ||
| 2026-07-03 23:00 | 1286.47 | ||
| 2026-07-04 05:00 | 1286.53 | ||
| 2026-07-04 11:00 | 1286.6 | ||
| 2026-07-04 17:00 | 1286.67 | ||
| 2026-07-04 23:00 | 1286.73 | ||
| 2026-07-05 05:00 | 1286.8 | ||
| 2026-07-05 11:00 | 1286.87 | ||
| 2026-07-05 17:00 | 1286.93 | ||
| 2026-07-05 23:00 | 1287 | ||
| 2026-07-06 05:00 | 1287.11 | ||