<Tr> <Td> 9 April of each year </Td> <Td> Marking Vimy Ridge Day </Td> </Tr> <Tr> <Td> Varies </Td> <Td> The annual memorial service on Parliament Hill to remember deceased parliamentarians </Td> </Tr> <P> On occasion discretion can dictate the flying of the national flag at half - mast, not only on the Peace Tower, but on all federal facilities . Some examples include 11 September 2001, 11 September 2002, the 2004 Indian Ocean tsunami, the 2005 Mayerthorpe tragedy, the death of Pope John Paul II, the 2005 London bombings, the death of Smokey Smith, the state funerals of former U.S. presidents Ronald Reagan and Gerald Ford, and the death of Jack Layton </P> <P> There are, however, exceptions to the rules of half - masting in Canada: if Victoria Day or Canada Day fall during a period of half - masting, the flags are to be returned to full - mast for the duration of the day . The national flag on the Peace Tower is also hoisted to full mast if a foreign head of state or head of government is visiting the parliament . These exemptions, though, do not apply to the period of mourning for the death of a Canadian monarch . The Royal Standard of Canada also never flies at half - mast, as it is considered representative of the sovereign, who ascends to the throne automatically upon the death of his or her predecessor . Each province can make its own determination of when to fly the flag at half - mast when provincial leaders or honoured citizens pass away . </P>

Who authorizes the flag to be flown at half staff