This is an interesting thread. I recently picked up a book by Hugh Maslen Jones "Countdown to Rescue" published in the 1980s. It recounts numerous tragic incidents during his time as a member of the Llanberis MRT. It should be compulsory reading for all those contemplating winter walking on Snowdon. I say winter but as the tales of woe report - you can get atrocious weather on Snowdon at any time of the year. The author was an early adopter of search and rescue dogs and numerous reports show their value in searches over large areas. Of course the technology available then predates mobile phones and SARLOC etc.
When I started hillwaking about 9 years ago, the group was led by a member of the Kinder MRT. At the October post-walk drink, he went through with us the contents of his rucksack and asked us to get properly equipped with survival bag, and head torch etc. I've manged to avoid using the head torch, so far.
Dave