In his 15 years with the organisation he has responded to a dozen emergency missions around the Pacific, and keeps a packed suitcase handy for whenever a call-up comes.
As a member of the Field Assessment and Co-ordination Team (Fact), he would go to the country ravaged by Cyclone Pam to assess the damage and determine what was needed. Items such as tents and water containers, as well as specialist personnel and financial support could be required.
''We determine these needs quickly so the rest of the world - the Red Cross societies - can see what is needed.''
His missions normally last about a month, ''and obviously the repercussions of an event like this are very much longer''.
''So when we are there we start to think of the longer-term things that Red Cross can do, and during that time we recruit people who will take over from us for the recovery stage.''
Mr Clark gave up a fulltime teaching job for casual teaching so he could be available at short notice. His most challenging experience - the 2004 Boxing Day tsunami - was his first as a Fact member, and ''that was pretty horrific''.
''It is incredibly hard work. It can be frustrating, but satisfying, in the sense that you come away and see the results of your work, and they are usually positive.''
