AAT recently contacted Forestry Tasmania re access to Lake Rowallan and were told all access roads to Lake Rowallan have been closed including the Borradaile Plains access. The Parangana bridge is out and there have been massive washouts and landslides with vast quantities of replacement fill to be put in place eg 70,000 m3 in one washout.
Remedial work has started and will take some time (months not weeks) and this is the reason roads have been closed.
A video by Rod How is available on YouTube - https://www.youtube.com/watch?v=sLafM92cLn0
Thanks to Rod for making this video public.