COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-08-16 10:10 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-08-17 00:00 | 1280.75 | 2026-08-17 11:00 | 1280.25 |
| 2026-08-16 00:00 | 1281.13 | 2026-08-17 17:00 | 1280.14 |
| 2026-08-15 00:00 | 1281.59 | 2026-08-17 23:00 | 1280.03 |
| 2026-08-14 00:00 | 1281.88 | 2026-08-18 05:00 | 1279.92 |
| 2026-08-13 00:00 | 1282.11 | 2026-08-18 11:00 | 1279.82 |
| 2026-08-12 00:00 | 1282.46 | 2026-08-18 17:00 | 1279.71 |
| 2026-08-11 00:00 | 1282.75 | 2026-08-18 23:00 | 1279.62 |
| 2026-08-10 00:00 | 1282.83 | 2026-08-19 05:00 | 1279.52 |
| 2026-08-09 00:00 | 1283 | 2026-08-19 11:00 | 1279.43 |
| 2026-08-08 00:00 | 1283.34 | 2026-08-19 17:00 | 1279.34 |
| 2026-08-07 00:00 | 1283.62 | 2026-08-19 23:00 | 1279.25 |
| 2026-08-20 05:00 | 1279.15 | ||
| 2026-08-20 11:00 | 1279.06 | ||
| 2026-08-20 17:00 | 1278.96 | ||
| 2026-08-20 23:00 | 1278.85 | ||
| 2026-08-21 05:00 | 1278.75 | ||
| 2026-08-21 11:00 | 1278.64 | ||
| 2026-08-21 17:00 | 1278.54 | ||
| 2026-08-21 23:00 | 1278.43 | ||
| 2026-08-22 05:00 | 1278.32 | ||
| 2026-08-22 11:00 | 1278.22 | ||
| 2026-08-22 17:00 | 1278.11 | ||
| 2026-08-22 23:00 | 1278 | ||
| 2026-08-23 05:00 | 1277.9 | ||
| 2026-08-23 11:00 | 1277.79 | ||
| 2026-08-23 17:00 | 1277.69 | ||
| 2026-08-23 23:00 | 1277.58 | ||
| 2026-08-24 05:00 | 1277.48 | ||
| 2026-08-24 11:00 | 1277.37 | ||
| 2026-08-24 17:00 | 1277.27 | ||
| 2026-08-24 23:00 | 1277.16 | ||
| 2026-08-25 05:00 | 1277.16 | ||
| 2026-08-25 11:00 | 1277.15 | ||
| 2026-08-25 17:00 | 1277.14 | ||
| 2026-08-25 23:00 | 1277.14 | ||
| 2026-08-26 05:00 | 1277.13 | ||