This is what the actual order says.
THEREFORE, outdoor burning, the use of charcoal briquettes, and prescribed burns are banned on all forest lands within the State of Washington under Department of Natural Resources fire protection through September 30, 2021. This date may be extended or shortened based upon ongoing fire conditions. The following exceptions will apply:
1. As approved in writing by the Commissioner of Public Lands or Department Supervisor, approved prescribed fire for ecological purposes, when conducted by trained professionals.
2. As approved in writing by the Commissioner of Public Lands or Department Supervisor when there are compelling reasons for such an exception.
You should ask a Ranger. I would think propane is ok, it usually is.