COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-10-17 09:13 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-10-18 00:00 | 1286.82 | 2026-10-18 05:00 | 1286.93 |
| 2026-10-17 00:00 | 1286.48 | 2026-10-18 11:00 | 1286.94 |
| 2026-10-16 00:00 | 1285.99 | 2026-10-18 17:00 | 1286.95 |
| 2026-10-15 00:00 | 1285.62 | 2026-10-18 23:00 | 1286.95 |
| 2026-10-14 00:00 | 1285.31 | 2026-10-19 05:00 | 1286.98 |
| 2026-10-13 00:00 | 1285.21 | 2026-10-19 11:00 | 1287 |
| 2026-10-12 00:00 | 1285.3 | 2026-10-19 17:00 | 1287.02 |
| 2026-10-11 00:00 | 1285.52 | 2026-10-19 23:00 | 1287.04 |
| 2026-10-10 00:00 | 1285.69 | 2026-10-20 05:00 | 1287.06 |
| 2026-10-08 00:00 | 1286.14 | 2026-10-20 11:00 | 1287.09 |
| 2026-10-20 17:00 | 1287.11 | ||
| 2026-10-20 23:00 | 1287.13 | ||
| 2026-10-21 05:00 | 1287.15 | ||
| 2026-10-21 11:00 | 1287.17 | ||
| 2026-10-21 17:00 | 1287.19 | ||
| 2026-10-21 23:00 | 1287.22 | ||
| 2026-10-22 05:00 | 1287.24 | ||
| 2026-10-22 11:00 | 1287.26 | ||
| 2026-10-22 17:00 | 1287.28 | ||
| 2026-10-22 23:00 | 1287.3 | ||
| 2026-10-23 05:00 | 1287.32 | ||
| 2026-10-23 11:00 | 1287.35 | ||
| 2026-10-23 17:00 | 1287.37 | ||
| 2026-10-23 23:00 | 1287.39 | ||
| 2026-10-24 05:00 | 1287.41 | ||
| 2026-10-24 11:00 | 1287.43 | ||
| 2026-10-24 17:00 | 1287.45 | ||
| 2026-10-24 23:00 | 1287.48 | ||
| 2026-10-25 05:00 | 1287.5 | ||
| 2026-10-25 11:00 | 1287.52 | ||
| 2026-10-25 17:00 | 1287.54 | ||
| 2026-10-25 23:00 | 1287.56 | ||
| 2026-10-26 05:00 | 1287.58 | ||
| 2026-10-26 11:00 | 1287.61 | ||
| 2026-10-26 17:00 | 1287.63 | ||
| 2026-10-26 23:00 | 1287.65 | ||
| 2026-10-27 05:00 | 1287.67 | ||