example of inquiry:

<conditions>
  <trp_skiDestination>312</trp_skiDestination>
   (...)

You can ask for a few regions (then they should be separated by commas).

<conditions>
  <trp_skiDestination>312,413</trp_skiDestination>
   (...)

File with the list of regions is always available at http://merlinx.pl/mdsws/skireg.csv