Sales of home sites along the Snake River have been driving a huge bump in sales volume so far in 2012. Vacant land sales in Jackson Hole in 2012 have already exceeded the entirety of 2011 with more than four months remaining. And 2010. And 2009. And, with just one more sale this year, Jackson Hole building site closings will also exceed 2008. With seven closings already reported in August, unit sales...