You’ve got a hike planned. But it’s raining, pouring, dumping outside. Just go, says Jennifer Aist, the author of the book “Babes in the Woods,” a guide to hiking, camping and boating with babies and small children. “If you live in the Pacific Northwest, you need to embrace the wet,” Aist says. “Otherwise you’ll rot away on your couch.” An Alaska resident, Jennifer’s been on plenty of hikes with her three kids in Washington State and British Columbia. She knows rainy days. “I can’t tell you how many hours I have spent in the rain in campgrounds, on trails and on beaches,” Aist says. But rain is a magical, surprising…