COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-06-16 14:43 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-06-16 00:00 | 1281.16 | 2026-06-16 17:00 | 1281.52 |
| 2026-06-15 00:00 | 1281.43 | 2026-06-16 23:00 | 1281.58 |
| 2026-06-14 00:00 | 1281.55 | 2026-06-17 05:00 | 1281.66 |
| 2026-06-13 00:00 | 1281.58 | 2026-06-17 11:00 | 1281.73 |
| 2026-06-12 00:00 | 1281.06 | 2026-06-17 17:00 | 1281.81 |
| 2026-06-11 00:00 | 1280.08 | 2026-06-17 23:00 | 1281.88 |
| 2026-06-10 00:00 | 1278.74 | 2026-06-18 05:00 | 1281.95 |
| 2026-06-09 00:00 | 1277.83 | 2026-06-18 11:00 | 1282.01 |
| 2026-06-08 00:00 | 1277.18 | 2026-06-18 17:00 | 1282.07 |
| 2026-06-07 00:00 | 1276.41 | 2026-06-18 23:00 | 1282.12 |
| 2026-06-06 00:00 | 1275.95 | 2026-06-19 05:00 | 1282.17 |
| 2026-06-19 11:00 | 1282.21 | ||
| 2026-06-19 17:00 | 1282.26 | ||
| 2026-06-19 23:00 | 1282.31 | ||
| 2026-06-20 05:00 | 1282.35 | ||
| 2026-06-20 11:00 | 1282.41 | ||
| 2026-06-20 17:00 | 1282.47 | ||
| 2026-06-20 23:00 | 1282.54 | ||
| 2026-06-21 05:00 | 1282.61 | ||
| 2026-06-21 11:00 | 1282.68 | ||
| 2026-06-21 17:00 | 1282.76 | ||
| 2026-06-21 23:00 | 1282.84 | ||
| 2026-06-22 05:00 | 1282.92 | ||
| 2026-06-22 11:00 | 1282.99 | ||
| 2026-06-22 17:00 | 1283.07 | ||
| 2026-06-22 23:00 | 1283.15 | ||
| 2026-06-23 05:00 | 1283.22 | ||
| 2026-06-23 11:00 | 1283.3 | ||
| 2026-06-23 17:00 | 1283.38 | ||
| 2026-06-23 23:00 | 1283.46 | ||
| 2026-06-24 05:00 | 1283.53 | ||
| 2026-06-24 11:00 | 1283.61 | ||
| 2026-06-24 17:00 | 1283.69 | ||
| 2026-06-24 23:00 | 1283.76 | ||
| 2026-06-25 05:00 | 1283.84 | ||
| 2026-06-25 11:00 | 1283.92 | ||
| 2026-06-25 17:00 | 1284 | ||
| 2026-06-25 23:00 | 1284.07 | ||
| 2026-06-26 05:00 | 1284.15 | ||