A fiscal flood that threatens to swamp local government budgets across the U.S. overflows from file cabinets in the office of Patty Halm, chair of the Michigan Tax Tribunal.

The backlog of cases from taxpayers seeking to lower property-tax bills of more than $100,000 shot up to 14,236 this year from an annual average of about 6,000 during the past decade. The backlog of smaller claims was at 28,558 at the end of September, eight times higher than a decade ago, according to records at the tribunal, a Lansing-based administrative court.