COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-06-11 10:35 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-06-11 00:00 | 1280.08 | 2026-06-11 17:00 | 1281.25 |
| 2026-06-10 00:00 | 1278.74 | 2026-06-11 23:00 | 1281.46 |
| 2026-06-09 00:00 | 1277.83 | 2026-06-12 05:00 | 1281.65 |
| 2026-06-08 00:00 | 1277.18 | 2026-06-12 11:00 | 1281.84 |
| 2026-06-07 00:00 | 1276.41 | 2026-06-12 17:00 | 1282.02 |
| 2026-06-06 00:00 | 1275.95 | 2026-06-12 23:00 | 1282.19 |
| 2026-06-05 00:00 | 1275.47 | 2026-06-13 05:00 | 1282.35 |
| 2026-06-04 00:00 | 1275.22 | 2026-06-13 11:00 | 1282.52 |
| 2026-06-03 00:00 | 1274.97 | 2026-06-13 17:00 | 1282.65 |
| 2026-06-02 00:00 | 1274.57 | 2026-06-13 23:00 | 1282.72 |
| 2026-06-01 00:00 | 1273.64 | 2026-06-14 05:00 | 1282.77 |
| 2026-06-14 11:00 | 1282.81 | ||
| 2026-06-14 17:00 | 1282.84 | ||
| 2026-06-14 23:00 | 1282.88 | ||
| 2026-06-15 05:00 | 1282.91 | ||
| 2026-06-15 11:00 | 1282.93 | ||
| 2026-06-15 17:00 | 1282.95 | ||
| 2026-06-15 23:00 | 1282.97 | ||
| 2026-06-16 05:00 | 1282.99 | ||
| 2026-06-16 11:00 | 1283.08 | ||
| 2026-06-16 17:00 | 1283.18 | ||
| 2026-06-16 23:00 | 1283.27 | ||
| 2026-06-17 05:00 | 1283.37 | ||
| 2026-06-17 11:00 | 1283.47 | ||
| 2026-06-17 17:00 | 1283.56 | ||
| 2026-06-17 23:00 | 1283.66 | ||
| 2026-06-18 05:00 | 1283.75 | ||
| 2026-06-18 11:00 | 1283.85 | ||
| 2026-06-18 17:00 | 1283.95 | ||
| 2026-06-18 23:00 | 1284.04 | ||
| 2026-06-19 05:00 | 1284.14 | ||
| 2026-06-19 11:00 | 1284.23 | ||
| 2026-06-19 17:00 | 1284.33 | ||
| 2026-06-19 23:00 | 1284.42 | ||
| 2026-06-20 05:00 | 1284.52 | ||
| 2026-06-20 11:00 | 1284.62 | ||
| 2026-06-20 17:00 | 1284.71 | ||
| 2026-06-20 23:00 | 1284.81 | ||
| 2026-06-21 05:00 | 1284.9 | ||