COLUMBIA--GRAND COULEE DAM (GCDW1)
| Observed | Forecast/Trend Issued: 2026-06-01 15:32 PDT | ||
| Date/Time (PDT) | Pool Height | Date/Time (PDT) | Pool Height |
| 2026-06-02 00:00 | 1274.57 | 2026-06-02 11:00 | 1275.31 |
| 2026-06-01 00:00 | 1273.64 | 2026-06-02 17:00 | 1275.49 |
| 2026-05-31 00:00 | 1271.93 | 2026-06-02 23:00 | 1275.66 |
| 2026-05-30 00:00 | 1270.22 | 2026-06-03 05:00 | 1275.83 |
| 2026-05-29 00:00 | 1269.38 | 2026-06-03 11:00 | 1276 |
| 2026-05-28 00:00 | 1268.89 | 2026-06-03 17:00 | 1276.17 |
| 2026-05-27 00:00 | 1268.13 | 2026-06-03 23:00 | 1276.33 |
| 2026-05-26 00:00 | 1267.39 | 2026-06-04 05:00 | 1276.49 |
| 2026-05-25 00:00 | 1266.66 | 2026-06-04 11:00 | 1276.65 |
| 2026-05-24 00:00 | 1265.46 | 2026-06-04 17:00 | 1276.81 |
| 2026-05-23 00:00 | 1264.92 | 2026-06-04 23:00 | 1276.97 |
| 2026-06-05 05:00 | 1277.13 | ||
| 2026-06-05 11:00 | 1277.29 | ||
| 2026-06-05 17:00 | 1277.44 | ||
| 2026-06-05 23:00 | 1277.6 | ||
| 2026-06-06 05:00 | 1277.77 | ||
| 2026-06-06 11:00 | 1277.95 | ||
| 2026-06-06 17:00 | 1278.16 | ||
| 2026-06-06 23:00 | 1278.41 | ||
| 2026-06-07 05:00 | 1278.66 | ||
| 2026-06-07 11:00 | 1278.91 | ||
| 2026-06-07 17:00 | 1279.13 | ||
| 2026-06-07 23:00 | 1279.32 | ||
| 2026-06-08 05:00 | 1279.51 | ||
| 2026-06-08 11:00 | 1279.7 | ||
| 2026-06-08 17:00 | 1279.89 | ||
| 2026-06-08 23:00 | 1280.08 | ||
| 2026-06-09 05:00 | 1280.26 | ||
| 2026-06-09 11:00 | 1280.43 | ||
| 2026-06-09 17:00 | 1280.6 | ||
| 2026-06-09 23:00 | 1280.77 | ||
| 2026-06-10 05:00 | 1280.93 | ||
| 2026-06-10 11:00 | 1281.08 | ||
| 2026-06-10 17:00 | 1281.23 | ||
| 2026-06-10 23:00 | 1281.36 | ||
| 2026-06-11 05:00 | 1281.49 | ||