Question

if you are on a 29.2 degree slope and an avalanche started 236 m up the slope how much time would you have to get out of the way

Answer 1

A bit longer than it takes an object to fall 236 m, straight down. That would be sqrt(2H/g) = 4.9 seconds. An exact solution would be rather complicated. A pressure wave will go through the snow and an air pressure wave will eventually form in front of the advancing front. Pressure waves may speed up the avalanche, while the falling snow is retarded by surface snow ahead of it.

The teacher may expect you to assume something like frictionless motion down the slope, but it isn't that simple.

Answer 2

You may find this previous answer interesting:
http://www.science-facts.com/weather-climate/avalanche-speeds-explained/