Where did the clovis tribe come from?

In many ways, the Clovis people seem to appear by magic on the North American continent. The assumption has been that their ancestors moved south from Alaska, pursuing their favorite prey, the mammoth. However, there are no Clovis sites in either Alaska or Canada; likewise, there are no technological antecedants for Clovis anywhere in the Americas nor are their any technological antecedants in northeast Asia, extreme eastern Asia, or anywhere in Asia. So from where did the Clovis people come - or at least, from where did their technology of producing finely crafted, fluted spear points, come?