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Brian Stoecker/Turnagain Times A bore tide plies Turnagain Arm, north of Girdwood in early February. Its accompanying high tide was similar in volume to the one predicted for Wednesday, March 11. |
By Brian Stoecker
Turnagain Times Correspondent
The forthcoming full moon, coupled with Earth’s seasonal proximity to the sun, will generate extreme Turnagain Arm tides from March 9-13 (Monday through Friday). This may provide the best bore tide viewing until late July. The peak tide of 36.3 feet (including the plus 4.2 ft correction at Sunrise) on Wednesday, March 11, will be matched by only one other afternoon or evening tide between now and mid-August.
Winter bore tides provide the opportunity to see them collide with landlocked ice. Some collisions are rather impressive Some viewers even place friendly wagers on whether or not the bore will roll a berg.
Winter bores do not generally build as high or readily as their summer counterparts from equal tides, thus they’re not as reliable to the north of Hope or south of Girdwood. They also arrive at points along the Arm, earlier than expected in summer (Conjecture: Reduced pressure from the lack of rain and melt water is the contributing factor).
The week’s premier bore tide (March 11) should be advancing from Hope to Sunrise at 5 p.m. (about two hours after the Anchorage low tide). It should clear Bird Point, making its way toward Girdwood by 5:30 p.m. (low tide plus 2.5 hours). But as the winter bore’s schedule is suspect, consider arriving early.
Turnagain Arm’s semidiurnal tide takes over 24 hours to complete its cycle, thus the bore arrives later in each successive day—consult your tide book to predict additional arrival times. Otherwise, consider that it will arrive about 45 minutes later than it did the previous day (that formula works for the week in question, though is otherwise inconsistent).
Iceberg surfing during extreme tides or otherwise is not recommended.