Unfortunately, the SAR tacaid doesn't have the best info on power checks for an LZ -- Chapter 9 of all the H60 manuals goes into much better depth about the how you should approach a mountain LZ. The absolute minimum is 4 approaches to allow you determine wind (2 approaches), 1 as a "practice approach", and 1 last approach a landing with an option for a waveoff. Winds in the mountains are not steady, but I am sure the crew would have noticed that they downdrafts or that they were about to make a downwind approach had they used the NATOPS procedures.
The SAR tacaid is a multi platform pub -- the NATOPS gives a far better explanation on how to get into an LZ with an H60.