The Spring Thaw is part of a three-event series that continues on March 21 at Fountainhead Regional Park and April 11 back at Willowsford. For more information regarding the event, contact [email protected] It’s been a long winter. Time to dust off the mountain bike, pump some air in the tires, and get ready to roll. The Rev# Spring Thaw Trail Series offers rides on moderatley challenging, purpose-built singletrack at Willowsford Conservancy lands near Ashburn, Va. Rides for all ages and abilities kick off at 12:30. Bikers pass through open fields and dense forests on the rolling course. Experts ride three loops (20.8 miles); weekend warriors can choose two loops (13.8 miles); newbies ride a single 6.8-mile loop.If you prefer two feet over two wheels, the Spring Thaw 10K and 5K trail runs will keep you on your toes. Runners can expect to be mud-splattered and wet-footed after the recent rains. The trail races start at 10 a.m.