http://www.tc.gc.ca/CivilAviation/pu...C/2-1.htm#2-12
2.12 Mountainous Regions
Designated mountainous regions are areas of defined lateral dimensions specified in the Designated Airspace Handbook, above which special rules concerning minimum IFR altitudes to ensure obstacle clearance (CAR 602.124) apply.
An aircraft, when operated in accordance with IFR within designated mountainous regions, but outside of areas for which minimum altitudes for IFR operations have been established (including minimum radar vectoring altitudes, MOCAs, transition altitudes, 100NM safe altitudes, MSAs and AMAs), shall be flown at an altitude of at least 2000 feet above the highest obstacle within 5NM of the aircraft in flight when in areas 1 and 5, and at least 1500 feet above the highest obstacle within 5NM when in areas 2, 3 and 4. (See Figure 2.10.)
As minimum enroute IFR altitudes have been established for designated airways and air routes, such minimum altitudes shall be applied when flying in accordance with IFR along airways or air routes within designated mountainous regions, except that aircraft should be operated at an altitude which is at least 1000 feet higher than the minimum enroute IFR altitude, when there are large variations in temperature and (or) pressure. (See RAC 8.5)
Figure 2.10 – Designated Mountainous Regions in Canada