COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-04-26 15:09 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-04-26 00:00 | 1253.57 | 2026-04-26 23:00 | 1253.52 |
| 2026-04-25 00:00 | 1253.44 | 2026-04-27 05:00 | 1253.44 |
| 2026-04-24 00:00 | 1253.3 | 2026-04-27 11:00 | 1253.35 |
| 2026-04-23 00:00 | 1253.13 | 2026-04-27 17:00 | 1253.26 |
| 2026-04-22 00:00 | 1252.85 | 2026-04-27 23:00 | 1253.17 |
| 2026-04-21 00:00 | 1252.96 | 2026-04-28 05:00 | 1253.09 |
| 2026-04-20 00:00 | 1253.68 | 2026-04-28 11:00 | 1253 |
| 2026-04-19 00:00 | 1253.49 | 2026-04-28 17:00 | 1253 |
| 2026-04-18 00:00 | 1253.58 | 2026-04-28 23:00 | 1253 |
| 2026-04-17 00:00 | 1253.46 | 2026-04-29 05:00 | 1253 |
| 2026-04-16 00:00 | 1253.26 | 2026-04-29 11:00 | 1253 |
| 2026-04-29 17:00 | 1253 | ||
| 2026-04-29 23:00 | 1253 | ||
| 2026-04-30 05:00 | 1253 | ||
| 2026-04-30 11:00 | 1253 | ||
| 2026-04-30 17:00 | 1253 | ||
| 2026-04-30 23:00 | 1253 | ||
| 2026-05-01 05:00 | 1253 | ||
| 2026-05-01 11:00 | 1253 | ||
| 2026-05-01 17:00 | 1253 | ||
| 2026-05-01 23:00 | 1253 | ||
| 2026-05-02 05:00 | 1253 | ||
| 2026-05-02 11:00 | 1253 | ||
| 2026-05-02 17:00 | 1253 | ||
| 2026-05-02 23:00 | 1253 | ||
| 2026-05-03 05:00 | 1253 | ||
| 2026-05-03 11:00 | 1253 | ||
| 2026-05-03 17:00 | 1253 | ||
| 2026-05-03 23:00 | 1253 | ||
| 2026-05-04 05:00 | 1253 | ||
| 2026-05-04 11:00 | 1253 | ||
| 2026-05-04 17:00 | 1253 | ||
| 2026-05-04 23:00 | 1253 | ||
| 2026-05-05 05:00 | 1253 | ||
| 2026-05-05 11:00 | 1253 | ||
| 2026-05-05 17:00 | 1253 | ||
| 2026-05-05 23:00 | 1253 | ||
| 2026-05-06 05:00 | 1253 | ||