A
bastion was also the name given to areas in the Arctic ocean where
Soviet navy
Northern Fleet SSBNs were to dash for safety during a conflict. Since Soviet
boomers spent much more time in port, odds were higher that they'd be
flushed from dockside.
Since they wouldn't have a large area to run in when NATO ASW forces blocked off the GIUK, the plan was to have them run for the polar icecap. They would patrol there, protected by SSNs from NATO boats, until needed.