COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-10-27 08:18 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-10-28 00:00 | 1288.64 | 2026-10-28 11:00 | 1288.81 |
| 2026-10-27 00:00 | 1288.29 | 2026-10-28 17:00 | 1288.85 |
| 2026-10-26 00:00 | 1288.03 | 2026-10-28 23:00 | 1288.88 |
| 2026-10-25 00:00 | 1287.76 | 2026-10-29 05:00 | 1288.92 |
| 2026-10-24 00:00 | 1287.52 | 2026-10-29 11:00 | 1288.95 |
| 2026-10-23 00:00 | 1287.37 | 2026-10-29 17:00 | 1288.98 |
| 2026-10-22 00:00 | 1287.27 | 2026-10-29 23:00 | 1289.01 |
| 2026-10-21 00:00 | 1287.2 | 2026-10-30 05:00 | 1288.98 |
| 2026-10-20 00:00 | 1287.04 | 2026-10-30 11:00 | 1288.88 |
| 2026-10-19 00:00 | 1286.9 | 2026-10-30 17:00 | 1288.76 |
| 2026-10-18 00:00 | 1286.82 | 2026-10-30 23:00 | 1288.63 |
| 2026-10-31 05:00 | 1288.47 | ||
| 2026-10-31 11:00 | 1288.31 | ||
| 2026-10-31 17:00 | 1288.12 | ||
| 2026-11-01 00:00 | 1287.92 | ||
| 2026-11-01 05:00 | 1287.7 | ||
| 2026-11-01 11:00 | 1287.47 | ||
| 2026-11-01 17:00 | 1287.25 | ||
| 2026-11-01 23:00 | 1287.02 | ||
| 2026-11-02 05:00 | 1286.79 | ||
| 2026-11-02 11:00 | 1286.57 | ||
| 2026-11-02 17:00 | 1286.34 | ||
| 2026-11-02 23:00 | 1286.11 | ||
| 2026-11-03 05:00 | 1285.89 | ||
| 2026-11-03 11:00 | 1285.66 | ||
| 2026-11-03 17:00 | 1285.44 | ||
| 2026-11-03 23:00 | 1285.21 | ||
| 2026-11-04 05:00 | 1284.98 | ||
| 2026-11-04 11:00 | 1284.75 | ||
| 2026-11-04 17:00 | 1284.52 | ||
| 2026-11-04 23:00 | 1284.29 | ||
| 2026-11-05 05:00 | 1284.06 | ||
| 2026-11-05 11:00 | 1283.83 | ||
| 2026-11-05 17:00 | 1283.61 | ||
| 2026-11-05 23:00 | 1283.39 | ||
| 2026-11-06 05:00 | 1283.19 | ||