Ed LaChapelle and Monty Atwater worked in Little Cottonwood Canyon in the 1950's.  Atwater put together Ten Contributory Factors for avalanche hazard evaluation in 1954. Check out his typewritten notes on direct action slab avalanches that are still relevant to today's avalanche problems. For further reading on contributory factors from Ron Perla there is a more in depth article from 1970 HERE.