This coverage is made possible through a partnership between Grist and Interlochen Public Radio in northern Michigan.  Flooding across northern Michigan last month pushed rivers to record levels, testing the limits of the state’s aging dams so severely that officials in one city nearly ordered evacuations as water threatened to spill over the top of a key barrier — a close call that highlights the growing risk that intensifying storms pose to similar infrastructure around the country. Nationwide, the average dam is 64 years old and most were built for rainfall patterns that no longer reflect today’s changing climate. Thousands are classified as high hazard, meaning their failure could result in the loss of life. Dam safety experts say inspections are uneven and improvements often underfunded. More than half of Michigan’s dams are beyond their 50-year design life, and the risks became clear as snowmelt and weeks of heavy rain swelled rivers.…