The sirens sounded for a second time in Fort Simpson, N.W.T., just before 3 p.m. on Sunday afternoon, signalling that water levels along the Mackenzie River had reached 15 metres. That triggered a final evacuation order for people who live on the island, which is home to about sixty per cent of Simpson's 1,200 residents. Emergency operation support staff will now go door to door to help anyone needing transportation to the recreation centre, where people are asked to register before moving on.