Imagine driving south on Saturday for a perfect spring picnic on Turnagain Arm. Shake off that winter weariness, pack a baguette and a jar of Nutella, and find a quiet overlook where you can toss out a blanket and watch the sun sizzle snow off the mountains. It's a relaxing picture, but there's one more reason to make the trip this weekend. Grab your binoculars, and for goodness' sake, stay out of the water. The new moon is here, and it's bore tide time. Like an army marching 25 miles up Turnagain Arm, the bore tide advances in one cascading...